Koi Diseases and Their Treatments

koi diseases

 

 

For a koi, life can be full of peril.  The fish in an outdoor pond are subject to not only birds of prey and raccoons but to things you often can’t see that live in your water and infect your fish.  Fortunately, there is a great deal of information on koi diseases and an equal amount of treatments but the most important thing is being informed on those diseases.  The more you know about koi maladies the better you can treat them. Listed below are most of the more common koi diseases and some of their treatments.

One of the most common diseases found in Koi is Ich. It is a protozoan that begins its growth in the pond and later attaches to the gills of the Koi as it matures. Ich can kill smaller Koi, especially in crowded ponds.

Tropical fish specialists frequently deal with Ich. It can, however, also infect cold water fish. An Ich infection shows up as a group of white spots dotted all over the body of the fish. They must attach to the fish within 48 hours of hatching or they will die. Once they attach themselves to fish, they dig into the skin and feed on the fish’s tissue. After feeding on the fish for approximately three weeks, they detach themselves and move to the bottom of the pond to reproduce. The Ich hatch out of cysts at the bottom of the pond and use small hair-like tentacles called cilia to swim about.

 

Treating Ich

 

There are a couple of widely used methods to treat ich.  The first one requires the koi owner to increase the salt concentration of the pond or quarantine tank to about 0.5% over a period of days.  At the same time increase the temperature of the water gradually to the high 70’s F while increasing aeration.  This is an effective and cheaper way to deal with the ich protozoan.  The second method is a tried and true method for dealing with parasites in general and involves malachite green and formalin.  Using both simultaneously is definitely going to be effective against ich but you may be able to simply treat with malachite green alone.  For short treatments in quarantine, one could do a quantity of 1.5 mg of malachite green for every liter of water for up to 1 hour (or 6mg of malachite green for every gallon of water).  Always wear gloves when handling both malachite green and formalin.

Dropsy

Fish that have dropsy often show signs of swelling or lifting of the scales.  Their eyes will frequently bulge. If you ever notice this, don’t hesitate to separate the infected fish from the others. Paying careful attention to your fish in order to notice these symptoms as early as possible means that your fish stand a better chance of surviving. Dropsy is curable, even though common understanding of it suggests otherwise. It can be cured with one of many of the anti-bacterial products found in pet stores today.

Tail Rot

Tail rot and fin rot are really secondary to the original problem which could be stress or poor water quality that is causing your koi to be immuno-compromised in the first place.  Once they are weakened then the already-present bacteria can move in a cause physical damage to your koi’s fins.

Treating Tail Rot

One good start to treating this malady is by a 30 -50% water change of your pond. Using Mela-Fix is also a great option for dealing with the bacteria themselves and you can also add salt to your pond which will go to work on your bacteria and also lower stress levels for your koi.  If you’d like you can also feed them Medi-Koi (just as with the cloudy eye treatment).

Mouth Rot

Mouth rot is a symptom of something larger and that is usually poor water quality that is causing your fish’s health to be compromised and open to infection.  You’re going to want to stop feeding for the time being and start improving your water quality by doing a 30% water change.  Next thing would be a light salt bath treatment and perhaps a treatment of Mela-Fix. You will also want to monitor your water quality by testing it regularly.  You can also remove the fish and treat the sores with hydrogen peroxide or iodine.

 

Anchor worm, also known as Lernea is a crustacean parasite that attaches to, and digs into the skin of fish. The female Lernea attaches to fish while males do not. The worm feeds on the fish, damaging its tissue. This leads to a bacterial and/or fungal infection on the fish. Another crustacean parasite, Argulus also attaches itself to fish and causes damage to tissue. Argulus have eight legs and rounded bodies. They also have to big suckers which are used to attach to the fish. Their appearance leads to their nickname, fish lice. These parasites can cause considerable irritation to fish and can lead to bacterial infections.

Treating Anchor Worm: They can be removed using tweezers or other small pincers. After removal, rub some Neosporin on the infected area. Use Dimilin or Dylox to treat the pond.

 

Some causes of fish infections, such as fungal hyphae or spores, require a microscope to see them. Mild or moderate infections can be treated and possibly cured if they are caught early. These types of fungal infections are not typically contagious and usually only a single Koi becomes infected. 

Treating Fungus: Fungus can be removed by gently rubbing the area with a cotton swab while the infected area must be treated with an antibiotic or antimicrobial cream immediately afterwards.

Fungal infections in fish almost always begin externally and start through a break in the outer skin layer of the fish. Affected Koi usually display fluffy or cotton-like growths on their skin. These growths may also exhibit a green tinge because of algae growth on the fungus. There may also be raised white, brown, yellow or green irregular bumps seen on the fish’s fins. Most infections can be successfully treated if caught early so it is important to visually inspect your fish frequently.

Your Koi fish may have  Lymphocystis, also known as Carp Pox if it has any buff discoloration on its skin. Another sign of Lymphocystis is shiny, greasy looking skin. This condition occurs when the water temperature in the fish’s environment has changed. Lymphocystis and Epistylis look alike, but they each respond differently when salt is added to the fish’s environment. Carefully watch the fish for a week after adding salt.  If you still notice the symptoms mentioned above, then the fish is suffering from Epistylis. Epistylis is an uncommon parasitic infection that is dangerous and can cause other diseases in your Koi. It is usually caused by poor management of the water, resulting in dirty water infected with parasites. If you do not regularly change the water in the pond, it can easily become a host to these parasites. Epistylis looks like a fungus and thrives in ulcers and wounds on Koi fish. You can identify an infected fish if you see white colored tufts in and around ulcers and wounds on the fish’s skin. Change the water in the pond and add salt to combat these parasites.

Its always nice to have a comprehensive reference manual you can look at when concerned about your koi’s health.  My “go to” manuals are the Manual of Koi Health and Koi Health and Disease (Ed. 2).  Edition 2 of “Koi Health and Disease” is supposed to be much more comprehensive than the first edition (the one I own) plus it has quick reference charts for disease diagnosis and its spiral bound for ease of use.

Fish normally eat less during the winter and by eating less, fish tend to lose a bit of weight. This normal change sometimes masks Skinny disease. The disease is caused by a bacterial infection that causes the fish to have a sucked-in gill appearance. Its head will often appear much bigger than the rest of its body.

Treatment: Adding extra food to the fish’s diet can usually clear up this disease. However, sometimes this doesn’t help and if the bacterial infection persists, adding erythromycin to the fish’s food normally clears the infection up quickly.

Cotton Wool Disease

Another disease Koi sometimes suffer is called Columnaris, which is sometimes also called Cotton Wool Disease. White threads in the fish’s mouth and a dry skin appearance are the main characteristics of this disease. Sometimes the color of the Koi becomes darker and white sores can appear on its skin. It is not always easy however to determine if the fish has the fungus in its gills. However, if the Koi stays near the surface of the pond, gulping for air, it is a good indication that the fungus is, in fact, in the gills. The Koi can also develop a soggy belly and a slimy coating over its skin.

Treatment: You can put potassium permanganate in the water to help clear up the condition. Additionally, injecting antibiotics and treating the wound directly will help care for the disease. You should separate the infected Koi from the population and treat the water so the other fish do not become infected.

Flukes

There are two main classes of flukes; 1) gill flukes and 2) skin flukes.  Both kinds are microscopic so if you suspect your fish are suffering from flukes you will need a microscope to verify it.  Dactylogyrus or gill flukes will attach to the gills and, as the name suggests, body flukes or gyrodactylus attach to the body.  Having hitch hikers is usually not a problem…except if you’re a koi and they are parasitic! Flukes tend to eat away at the protective “slime” coating of your fish thereby exposing them to harmful bacterial infections and causing ulcers.  They also are an irritant and cause your fish to itch and subsequently rub themselves on the bottom or side of the pond in an attempt to itch and rid themselves of the parasite.  Gill flukes can eat away at your koi’s gills so much that the koi will not be able to assimilate oxygen from the water.  If you suspect a fluke infection be sure to look out for this behavior.  

Treatment: You can quarantine but it is likely that your entire pond is afflicted with the flukes or their eggs so you can treat with medications like Aqua Prazzi,  potassium permanganate or Fluke Solve (both AquaPrazzi and Fluke Solve have the same active ingredient; “praziquantel”).  

 

Oodinium parasites can also cause disease in Koi. The disease caused is sometimes called Velvet Disease because it resembles a velvety golden dust, which covers the fish. Adding salt to the pond’s water does not normally clear up Velvet Disease. The best option is to add Formalin to the water as this has been shown to be most effective.

Costia

Costia, like Flukes, are a parasite.  In this case it is a microscopic flagellate that can reproduce rapidly.  Typically koi don’t suffer from costia unless they are already compromised in some way to begin with so it would be classified as a secondary illness.  Your koi will appear lethargic and will attempt to flash or rub on the sides or bottom of the pond to itch and rid themselves of the parasite. The skin will also appear whitish/grayish on the infected are of the koi’s body. Though these parasites can affect the skin they will also infect the gills of your koi as well.  

Treatment: There are treatment options for costia.  Malachite green and formalin can be used but you will need to make sure there is no salt in the pond to start with.  As with flukes, potassium permanganate can be used to treat costia.  Some practitioners will recommend a strong salt bath almost equivalent to that of ocean strength salt concentrations (around 3%).  Other treatments include trypaflavine which goes by the trade name Acriflavine and copper.  Copper is used because most invertebrates, like costia flagellates, have copper based blood (hemolymph) and therefore copper as a treatment in ponds is toxic to them.  Acriflavine should be added to your pond at a rate of 1ml/liter and copper is most appropriate at 2 mg/liter.  It is critical that you do not overdose with these two treatments.

White Spot 

If you notice that your Koi fish has white spots on its body, it may have a common disease known by the same name, White Spot. The disease can quickly multiply and spread to the other fish in your pond. White Spot is caused by a protozoan parasite that initially appears like little white grains of salt on your Koi. If left untreated, the parasite can cause other bacterial infections in your fish and can even be fatal to Koi. If you notice the parasite on your fish and notice that it later falls off, the pond’s infection is not cleared up. The parasite can reproduce at the bottom of your pond.

Pop Eye

Pop eye is also called exophthalmia and is really not linked to any one illness but is more of a symptom of something more.  It is a direct response to an excess of fluid or possibly gasses built up behind the eye which then cause the eye to bulge is distend.  There could be several things that could cause this to happen. Sometimes this malady is caused by a bacterial infection while other times it is due to trauma from running into the side of a concrete pond.  

Treatment: The best course of action is to immediately quarantine the fish and do a light salt bath. You will also want to greatly reduce feeding and how much you give it. You will also want to do 25% water changes daily and monitor water quality on a regular basis.

Cloudy Eye

Cloudy eye is somewhat uncommon but it can occur.  This malady is typically a symptom of something else going on rather than something attacking the eye specifically.  Some causes are bacterial infection, a cataract or even lack of the right kinds of foods (which is why you want to diversify their diet and feed them only quality food with less fillers). On rare occasions the reason could be a fluke on the eye but sometimes its a simple as physical damage to the eye by running into something in the pond.  Both eyes can have pop eye or just one, either is possible.

Treatment: Treatments for cloudy eye are a medicated koi food formulated to handle fungal and bacterial issues called Medi-Koi and or Mela-Fix. Mela-Fix is actually an oil extract from the Melaleuca tree mostly occurring in Australia and it has natural anti-bacterial properties.

Leeches

Unfortunately, leeches aren’t just looking for a free ride but also a free meal and eventually they will cause mortality of the host fish if left untreated.  Leeches can also transmit the koi disease known as SVC.  If you think your koi may be victims of leeches you can actually see them on their bodies as the leeches are not microscopic but other symptoms include a darkening or paling of the color of your koi as well as lethargy.  

Treatment: Some treatments for leeches include a product called Masoten which comes in powder form.  Another product is called malathion however many recommend against this treatment as it is an organophosphate insecticide and though it will kill leeches it may also harm your koi in the process.

 

Ulcers

Ulcers on the skin of your fish result from bacterial infections that form on scales, causing them to become red. The infection causes holes, or ulcers on the exterior of the fish and will eventually result in loss of scales if left untreated. These ulcers are most often caused by poor quality of the water in the pond. Maintain a healthy, clean pond and treat ulcers with an antibacterial to prevent any further occurrences.

One of the most common fungal infections found in Koi fish comes from the Saprolegnia fungus. Spores from the fungus can grow on any part of the fish, including its gills. The fungus first attacks the fish by germinating on dead tissue. The fungus has thread-like hyphae that release a substance that breaks down the tissue. As the fungal infection grows, these juices begin breaking down and destroying living tissue.

One of the easiest protozoan parasites to see under a microscope, and therefore confirm your fish is infected, is Trichodina. An infection with this parasite can be detected by a gray-white opaque appearance on the body of infected Koi. Trichodina is a warm water parasite and can survive in the water for a considerable amount of time without a host. Visually, they are perfectly round with hundreds of little hooks that look like cilia. It rotates continuously as it moves through mucus, causing damage to the Koi’s tissue. This parasite attacks both the skin and gills of your Koi.  Infected fish also often show symptoms such as flashing, rubbing and lethargy.

Treamtent: Treat this disease with potassium permanganate. If left untreated, the amount of damage to the fish’s gills can be significant.

Another parasite sometimes infecting Koi is the gill maggot. The parasite most often attacks the Koi’s gills and has a maggot-like egg sac appearance. It is a relatively uncommon parasite sometimes found in Koi ponds but when present, can cause Koi quite a bit of irritation. You will notice flicking and flashing and the gills become less efficient at absorbing oxygen. The most obvious sign of infection is seeing a Koi gasping for air at the surface of the pond.

Clearly there are quite a few little “beasties” out there that can make life miserable for your koi however there are a good deal more treatments these days as opposed to say 100 years ago.  Also, because the treatments are more potent these days there is a good chance that you can deal with a disease or parasite quite rapidly and not lose your prize breeding stock -or even just your favorite koi.

As mentioned previously, the two manuals I recommend having around for quick reference on disease are:

manual of koi health     and        Erik johnson koi health and disease

 

 

113 Responses to Koi Diseases and Their Treatments

  1. Jeff Chase says:

    Looks like I have a fish that has a fungal infection. Got caught in the skimmer box and now has like a green coat on a part of the skin

    • Koi-Care staff says:

      Jeff, Looks like the protective “slime” coat may be have gotten partially removed thereby inviting bacterial invasion on the skin. One solution that has worked for me in the past is a product called Mela-Fix. This product is an extract of the Melaleuca tree native to Australia and has natural anti-bacterial properties -really works great.

  2. Robert says:

    Not sure what has happened to my Koi, yesterday he didn’t come when I rang the dinner bell (tapping a rock with my toe). Today he was hanging out by the edge and I could see that his eyes are all clouded over otherwise he looks fine.

    • Koi-Care staff says:

      Most likely sounds like Cloudy Eye. This is a symptom of a bacterial infection. One thing you can do is a saltwater bath or a bath in an anti-bacterial like Myxazin.

  3. ken says:

    i have some small koi in a large aquarium. I will one move to my pond. Just noticed one swimming funny top fin closed and some red streaks on its body. what do you think?

    • Koi-Care staff says:

      res streaks is most likely a symptom of higher than normal ammonia. You need better filtration and/or reduce the the amount you’re feeding your koi.

  4. Chad Mullis says:

    Started losing fish about two weeks ago. All displayed redness and tissue loss around the mouth noticed at feeding time. Four down, but still have 20+ I’d like to save. Pond has been in stasis for several years, but earlier this summer I introduced 1) some new fish, and 2) duckweed from a very high-nutrient outflow. Any ideas?

    • Koi-Care staff says:

      Well I know koi will eat duckweed so under normal circumstances that shouldn’t be a problem unless the duckweed you transplanted came from water that may have somehow tainted the duckweed and subsequently sickened your fish. The other thing is that if you had no problems before then added some more fish, more fish than the system could handle then you may have a build up of ammonia from natural processes of koi metabolism. You may need to do a water change in your pond and/or a water filter cleaning. You’ll definitely want to test your water as your first step though.

  5. joe drewyor says:

    We have a pond of about 800-900 gallons. Have had a lot of rain lately and have started losing fish one at a time. In the past few days all the fish have started to be lethargic on the bottom and tend to have their noses to the walls. I checked ph and it is around 6-6.5; nitrates: NO2=.5; NO3=20.
    I removed a dead fish today which had died over night but had not bloated yet. Color not faded, I looked at the gills they were a pale( not red)I didn’t see any critters on them But I don’t really know what I am looking for).
    I added aquarium salt that directions said would treat 250 gallons and don’t really want to add more since now I am seeing sites that say not to add salt.
    What do I do here?

    • Koi-Care staff says:

      Though low levels of salt can mitigate the harmful effects of high nitrites (which you appear to have) the fact that they are lethargic and pale gills sounds to me like low dissolved oxygen. Minimum is 5.0 but 7.0 would be better. I don’t know if you have tested that or not. The new variable here sounds like an influx of rain water so I’m not sure how that would have caused a low DO situation. In my opinion ideal levels for nitrites should not exceed 0.2 mg/l and nitrates should fall somewhere between 20-60ppm. Sometimes you will see lethargic fish with high nitrates. pH should be somewhere around 7.0 – 8.5 and you want to be cautious of rapid pH changes. So at this point if you can maintain a low level of salt, do some 20% water changes and test for DO that would be a good start.
      Hope this helps.

  6. Roxanne says:

    I have 9 Koi in a 125 gallon aquarium. One of the fish has popeye which I have been treating with Melafix for over a week now. No apparent change in the popeye, BUT the fish has started spending 10 seconds or so lying on its right side on the bottom of the tank then righting itself and swimming around. Sometimes also listing to the right while swimming. Sometimes the fish looks good others it looks like it’s about to die. I cannot see anything on or about the fish that doesn’t look right except the left popeye. the right eye seems normal.

    Any suggestions?

    • Koi-Care staff says:

      Unfortunately pop eye isn’t associated with just one malady but in general it is from an excess of fluid or gases trapped behind the eye causing the eye to bulge. My first suggestion would be to make a quarantine tank if you don’t already have one and put your affected koi in that. Do regular 10-20 percent water changes everyday and reduce how much food you are giving that koi. In my experience, if Melafix is the solution to your problem you will see improvement relatively quickly (I’ve seen improvement overnight with melafix) so I would give it around 2 days but not much more if you don’t see improvement. If you fish is lying on its side that may be a sign of costia parasite. Costia can be dealt with by adding a little salt to y your quarantine tank. hope this helps

  7. darryl says:

    i have a koi that has developed a red spot on it, its scales are raised on that area and now there are 2 new spots on its other side. do you have any idea what this is,and how i can treat it because this morning i saw another fish with a red spot just like it.

    • Koi-Care staff says:

      Melissa, as with any health issue with koi the first order of business is to separate the affected fish into a quarantine and begin treatment to avoid any further infection spreading to the rest of the population. It sounds like your fish are suffering from some sort of ulcer typically brought about by a bacterial infection. Unfortunately it becomes a downhill slide because once a fish becomes infected and compromised that reduced health then allows for more infection and so on. So once in quarantine begin treatment with a salt bath (around 2.5 to 3.0 grams per liter). Allow the fish to be in there for a least a few days. You can also treat with an anti-bacterial as well, like Mela-Fix. Mela-fix usually works pretty quick, like around 24 to 48 hours.

  8. Kim says:

    Help
    We have had koi die that look perfectly well except that they lie on the bottom of the pond, struggling to get off it, within 24 hours they are dead. When a fish expert have looked at them under the microscope they can see nothing. Have you any suggestions on what we can do. The 2 koi that have died are approx. 5 months. They were small when we got them. The pond is not heated and it has no plants. The water has perfect reading and we change the water regularly.Thank you

    • Koi-Care staff says:

      Kim, it really could be a lot of things, for example someone could have been spraying for mosquitoes in your neighborhood with some getting into your pond. Your fish could have reacted with the insecticide so you would see nothing under the microscope. Sounds like your fish are lethargic -how is your dissolved oxygen? You don’t have plants and they normally do a good job of oxygenating the pond to a certain degree. Do you have any aeration?

  9. Bill Heinrich says:

    3 or 4 of my Koi have developed a condition not described above. They are having large holes develop in their bodies, where their exterior and scales are eaten down to their flesh. They are still acting normal and eating. I am treating the pond with Pondcare Melafix. Can you tell what this is and if the treatment will cure them. My pond is crystal clear with huge waterfall and Safio 6500 pump. Bill

    • Koi-Care staff says:

      Bill, from my website:
      “Ulcers on the skin of your fish result from bacterial infections that form on scales, causing them to become red. The infection causes holes, or ulcers on the exterior of the fish and will eventually result in loss of scales if left untreated. These ulcers are most often caused by poor quality of the water in the pond. Maintain a healthy, clean pond and treat ulcers with an antibacterial to prevent any further occurrences.”

      You could have something as simple as some leeches or flukes causing certain areas on the body to be exposed to bacteria already present in the pond which would make them compromised and subject to infection. I don’t know how big your pond is but if its large you may want to quarantine those affected fish and continue treatment with mela-fix and a light salt treatment and substitute your regular food for Medi-Koi. Regular 25% water changes are also a very good idea. Your pond is clear but when you’ve been testing it are you seeing any irregular readings?

  10. Rosemarie Griffith says:

    I have a large beautiful Sanke. The white has started going really pink, he is swimming O.K. although mostly on top and in the air stream, also not eating, any suggestions? I have given him two salt baths for a few hrs in a large vat with air bubble, he is too big to put in the large bowl.
    I have treated the pond a month ago with Malachite and Formalin, there are no sore on him??

    • Koi-Care staff says:

      Rosemarie, a few things on koi color. A lot of Japanese breeders will use specially formulated food to enhance the color of their koi. Additionally, water temps can have an effect on koi color-for example winter time and colder water mean brighter colors. Your koi is probably not getting food that is changing its color and its summer in the UK (which is where I think you are writing from) so most likely your koi is stressed. Being stressed can change the color of your fish and the fact that its not eating and is trying to get more dissolved oxygen probably means just that. I would check your filter, make sure its doing its job effectively. Also check your water quality and dissolved oxygen levels. Also try to check for things like organophosphates and hydrogen sulfide.

      • bebot says:

        Sir ., I HAve a koi fish and they are suffering from argulus parasite what should I do.,

        • Koi-Care staff says:

          Mark,
          From my site:
          “Argulus also attaches itself to fish and causes damage to tissue.
          Argulus have eight legs and rounded bodies. They also have to big
          suckers which are used to attach to the fish. Their appearance leads
          to their nickname, fish lice. These parasites can cause considerable
          irritation to fish and can lead to bacterial infections. They can be
          removed using tweezers or other small pincers. After removal, rub some
          Neosporin on the infected area. Use Dimilin or Dylox to treat the
          pond.”
          Dimilin, I believe, is now called Diflubenzuron.
          You’re going to want to treat this early as they can cause your fish
          to be compromised and thereby invite bacterial infections.

  11. Charlie Hagan says:

    We think our two koi have costia how can we treat it with melafix? And if not what else can we do to cure NEED HELP ASAP!!!

    • Koi-Care staff says:

      From my site:
      “There are treatment options for costia. Malachite green and formalin
      can be used but you will need to make sure there is no salt in the
      pond to start with. As with flukes, potassium permanganate can be
      used to treat costia. Some practitioners will recommend a strong salt
      bath almost equivalent to that of ocean strength salt concentrations
      (around 3%). Other treatments include trypaflavine which goes by the
      trade name Acriflavine and copper. Copper is used because most
      invertebrates, like costia flagellates, have copper based blood
      (hemolymph) and therefore copper as a treatment in ponds is toxic to
      them. Acriflavine should be added to your pond at a rate of 1ml/liter
      and copper is most appropriate at 2 mg/liter. It is critical that you
      do not overdose with these two treatments.”
      Sorry for the late reply. I don’t think melafix is going to deal with
      these parasites very well. Hopefully the above paragraph will help
      with your costia issues.
      -Koi-Care

  12. Nevin says:

    I have a collection of koi that I’ve kept for several years. During the winters I bring them indoors, which I recently did,(as my pond will freeze all the way, with, at its highest, 5-6 feet of snow on top). I noticed once I got them all in the tank that one fish has a large white patch between his eyes. there is also the same white stuff on one whisker, one nostril and one pectoral fin. It is raised and kind of fuzzy looking. the fish is otherwise overall healthy looking and acting. There is one other fish that has pop eye. My questions are what is the most effective and fastest acting treatment, can the two fish be treated together in quarantine and/or do I treat the whole tank and all the fish? this is the first problem in 5 years with these guys that I’ve had so I don’t really have a good clue what to do, and I really don’t want to lose ANY!

    • Koi-Care staff says:

      you’re going to want to quarantine each fish: for the white fuzzy infected fish (fungus) your going to want to treat with malachite green. There is a product called ProForm C that is an effective combination of Malachite green and formalin but make sure the water is on the cooler side and well aerated. You could also do a salt bath but that won’t be quite as effective (you can go up to 1 percent salt). Keep checking on the fish as its in the bath though and the duration should be maybe 30-40 minutes.
      For the pop eye there is a medicated food called Medi-Koi that may help but pop eye is an indication that something else is wrong not necessarily a direct cause and effect of one thing in particular. Medi-Koi is kind of a catch all for fungal and bacterial issues. Most likely you are experiencing some poor water conditions in your pond that is leading to these maladies.

  13. Leslie says:

    I have a black and white Koi. Today I noticed there is a hole the size of a dime just behind his right gill. Also, I noticed a blue line at the base of his tail. I inheritated the pond and the Koi, so I’m new to Koi.

    • Koi-Care staff says:

      I am forwarding a previous answer from my site:
      “Ulcers on the skin of your fish result from bacterial infections that form on scales, causing them to become red. The infection causes holes, or ulcers on the exterior of the fish and will eventually result in loss of scales if left untreated. These ulcers are most often caused by poor quality of the water in the pond. Maintain a healthy, clean pond and treat ulcers with an antibacterial to prevent any further occurrences.”

      You could have something as simple as some leeches or flukes causing certain areas on the body to be exposed to bacteria already present in the pond which would make them compromised and subject to infection. I don’t know how big your pond is but if its large you may want to quarantine those affected fish and continue treatment with mela-fix and a light salt treatment and substitute your regular food for Medi-Koi. Regular 25% water changes are also a very good idea. Your pond is clear but when you’ve been testing it are you seeing any irregular readings?

  14. Judy says:

    I suddenly lost a 2 year old koi yesterday! the tail fins were BLOOD red. today I noticed a few more with the same. I tested the water and everything was o except chlorine which was 6.0-8.0! what should I do? thanks, Judy

    • Koi-Care staff says:

      sorry for the late reply-well, you will definitely want to look into
      the source of your chorine and minimize that right off the bat.
      Chlorine will easily off gas if left alone especially if you have a
      vigorous aeration in your pond. If your levels are high then that
      must mean you have a constant supply of chlorinated water coming in.
      So more aeration, tablets to treat the chlorine such as sodium
      thiosulfate. Chlorine in higher conentrations is an oxidizer that can
      damage gill tissue and minimize the protective slime coat of fish
      opening them up to lots of maladies.
      hope this helps

  15. Judy says:

    I’m sorry; ammonia, not chlorine!

    • Koi-Care staff says:

      The short answer is yes, decaying plant material will definitely raise
      ammonia levels. Ammonia is essentially a nitrogenous waste and of
      course is excreted by your fish but also results from the breakdown of
      plant material via the natural decaying process. One thing you want
      to watch out for is high pH values when your ammonia is elevated
      because that’s when ammonia has a greater deleterious effect on your
      fish. I would continue water changes often (minimum of 25 percent)
      until the bacteria in your bio-filter have been able to catch up and
      handle the amount of ammonia in your system by converting it to
      nitrite.
      you may also want to get something to deal with your ammonia such as a
      detoxifier called Prime.

  16. June says:

    My white koi is in isolation for fin and tail rot and white cottony patches on his body. He seems to be responding well to Melafix, Pimafix, and pond salt, and is a little more active and his fins and tail are healing after 4 days of treatment. [Hurray!]

    I need advice because he was very weak when I started the treatment, and I would like to get him eating again. [I have some medicated food purchased specially for him.]

    This all started about a month ago… he magically appeared at feeding time after I thought the heron had eaten him along with some other fish when he disappeared two months before. When he reappeared, he had some serious tail and fin rot (all other fish were fine). I treated the whole pond with water changes and Melafix and his wounds were healing well, and he was eating and behaving normally. But when I came back from an 8 day business trip, I found him floating at the surface on his side under a water lily leaf (which is why my friend tending my pond didn’t see him.) {heavy sigh}

    So now he is in treatment in isolation he is improving daily, but I am worried about how thin he is and long it has been since he has eaten. So my questions are:

    How long can a sick koi go without food before it affects their health? I read that I am not supposed to feed during treatment, but is it a good idea to suspend treatment and try to get him to eat while in isolation? Or should I give him a vacation in the pond to see if he will eat? I am afraid he will just hide again — he is apparently great at hiding under the ledges, pots, and other places.

    Thank you for an advice you can offer. This is the first time I have had to treat a sick koi, and I really want to get him to a full recovery.

    • Koi-Care staff says:

      Sounds like you’re taking all the right steps to bring your koi back from the
      brink. You’ll read a lot about not feeding your koi during quarantine
      etc. and for the most part that’s good advice but at some point a lack
      of food and nutrition could cause a sort of downhill slide. Lack of
      nutrition for extended periods will make it more difficult to get your fish
      back easily and that time frame will depend on the size of the fish,
      water temperature etc. I would say if you are seeing real improvement
      and its in quarantine then I would try something like Medi-Koi and if
      it doesn’t eat ( or eats little) then simply pull out the uneaten
      food. You could even do something like pineapple or peas or other
      fresh vegs and fruits.

  17. April says:

    I have used Melafix on my pond to prepare for the long winter.
    One of the koi had started to float sideways. I went to the pet store and they told me to add charcoal to remove the medicine and do a water change. The koi is still floating sideways and I don’t know what else to do. i tested the water, it is fine.

    The pet store said the melafix makes the fish gill stick and it is hard for them to open it.

    Any solutions

    • Koi-Care staff says:

      I’ve never heard of Melafix having that effect on the gills of koi.
      I’ve always had a very good experience with it. Floating sideways
      sounds like it could be bacterial but realistically could be parasitic
      in nature as well. Unfortunately there is a lot that can go wrong with
      koi but you may want to try something like Medi-Koi if you don’t want
      to treat with Melafix.

  18. Ron says:

    I brought my fish indoors for the winter. They are staying in 100 gallon tanks. One tank is doing well, while the other has fish gasping at the surface next to bubblers and also by the filter. I have 4 bubblers and two filters pouring into the tank…..How could it possibly be a lack of oxygen? Lost my first fish today. Some are eating, while some are not.

    • Koi-Care staff says:

      (Koi-Care Staff):
      it probably isn’t the aeration. When you tested the water of each
      tank how does it look? Sounds like something(s) is off with respect
      to water chemistry in one tank.

      (Reader response):
      Thanks for the response regarding my koi issues. Upon doing more research, it seems that it may be a nitrate issue. A salting is suggested and that is the course of action which I’m trying. They are no longer gasping for oxygen at the surface bubblers or filters. They are swimming much more normally. Daily small percentage water change, too. Hopefully, this does the trick.

  19. Natalie says:

    I resently had a badamonia spike, lost several fish. Took out fish and drained pond, cleanedpond compleatly. Even power washed liner and rocks ect. Everything seened fine for a few months, then noticed blood streaks in one butterfly koi, now another has blood spots all over . Butterfly koi seems to be flicking and irritated. Been koi keeping for Many years with very little problems, don’t know what to do.

    • Koi-Care staff says:

      I’m not sure where you are located but if you were in a region where
      you experience seasonal changes and have trees nearby your pond you
      may be getting falling leaves into your pond. The decaying leaves in
      your pond have the capability to then raise your ammonia levels.
      Additionally, your bio-filter may be insufficient for whatever reason
      and need to be “re-booted” as it were with a fresh crop of nitrifying
      bacteria. Aquatic plants are always a good idea because they tend to
      assimilate nitrogenous waste well (ex. water hyacinth). Obviously
      water changes are going to be in order until ammonia levels start to
      fall but using an ammonia detoxifier such as Prime may be a good idea
      as well. I’m not sure what is causing the spike, especially after you
      cleaned your pond out so thoroughly but the fact that it keeps
      happening suggests to me that your main problem may lie within the
      bio-filter. Also, how is your aeration? A more vigorous aeration can
      also help speed along the process of getting ammonia out of the
      system.

  20. Bryce says:

    Thank You for all this information, it has helped me considerably. I only have one problem I cant figure out. I change my water and clean the filters once a month except at this time of year as it really isn’t needed. I have a mixed pond with mostly Koi and 2 Goldfish. One of my goldfish seems to have a large white “wart” looking protrusion on the side of it’s stomach. I’ve tried many different types of medications, such as Melafix, Parasite control, etc… I keep my PH in track with oyster shells and various additives if needed. I do have Carbon Powder i have no idea how to use. I have inherited this pond and learned to love it and learned on my own by posts just like these.

    For some reason I can’t find a solution to this guys problem. I also have severe bloating on the other Goldfish. Can these problems spread to my Koi as some are 15+ yrs old.

    • Koi-Care staff says:

      If your goldfish with the bloating is otherwise fine and still eating ok then that kind of thing is not entirely unheard of and may not adversely affect that fish (it doesn’t sound like a swim bladder disorder). If its bloated and and the scales are kind of raised then it would be something like dropsy. Your fish with the protrusion it sounds like a fungus of some description.
      This is from my site:
      Some causes of fish infections, such as fungal hyphae or spores, require a microscope to see them. Mild or moderate infections can be treated and possibly cured if they are caught early. These types of fungal infections are not typically contagious and usually only a single Koi becomes infected.

      Treating Fungus: Fungus can be removed by gently rubbing the area with a cotton swab while the infected area must be treated with an antibiotic or antimicrobial cream immediately afterwards.

      Fungal infections in fish almost always begin externally and start through a break in the outer skin layer of the fish. Affected Koi usually display fluffy or cotton-like growths on their skin. These growths may also exhibit a green tinge because of algae growth on the fungus. There may also be raised white, brown, yellow or green irregular bumps seen on the fish’s fins. Most infections can be successfully treated if caught early so it is important to visually inspect your fish frequently.

      I would definitely quarantine this fish if you have the facilities to do so and treat it by hand with an antibiotic cream like propolis after you have treated with a fungicide like malachite green. Both applications can be done with a cotton swab.

      Bryce, not familiar with carbon powder but if i had to guess it sounds like a derivation of activated charcoal whose function would be to reduce excess nutrients in your water and keep things like excessive algal growth to a minimum. If you anesthetize your fish first then use to the cotton swab to physically remove the fungal growth (if that is what it is) as well as treating it with malachite green- that is the objective. Then you will want to treat with some sort of antibiotic cream. Don’t worry about things washing off-that cream should lock it in. You don’t want your fish out of water for too long just like a person doesn’t want to be underwater for too long.

  21. Nathan says:

    Just wanted to say Thanks for the Great Detailed Guide
    Helped So Many Thanks

  22. Hpowell says:

    My koi have a tannish colored ball like things on their tails and fins what is the problem

    • Koi-Care staff says:

      Often times when winter rolls around and water temperatures drop one many experience some instances of carp pox which are raised bump-like structures on the fish’s body. Unfortunately there isn’t a treatment for it but it isn’t likely to kill your fish either. Carp pox will typically go away when the water warms up again. Another round, raised structure that could be on your koi is the argulus parasite but they are typically greenish in color so carp pox seems more likely in this case. Either way you can always add a little salt to your pond to make it easier on your koi- bring it up to about 4 or 5 parts per thousand.

  23. Shaun says:

    One of my pretty large koi has developed big/ bulging growth on two parts of the back. I separated it for almost five days and treated with Melafix and then rock salt for five days. No change – but now these pusy looking bulges are growing. I have consulted local pet stores, performed water changes etc. What else can I do? Am I going to lose this koi?

    • Koi-Care staff says:

      From my site about raised bumps.
      “Fungal infections in fish almost always begin externally and start through a break in the outer skin layer of the fish. Affected Koi usually display fluffy or cotton-like growths on their skin. These growths may also exhibit a green tinge because of algae growth on the fungus. There may also be raised white, brown, yellow or green irregular bumps seen on the fish’s fins. Most infections can be successfully treated if caught early so it is important to visually inspect your fish frequently.
      Treating Fungus: Fungus can be removed by gently rubbing the area with a cotton swab while the infected area must be treated with an antibiotic or antimicrobial cream immediately afterwards.”

      So a fungal infection is one possibility. The other possibility is Costia-see below.

      “Costia, like Flukes, are a parasite. In this case it is a microscopic flagellate that can reproduce rapidly. Typically koi don’t suffer from costia unless they are already compromised in some way to begin with so it would be classified as a secondary illness. Your koi will appear lethargic and will attempt to flash or rub on the sides or bottom of the pond to itch and rid themselves of the parasite. The skin will also appear whitish/grayish on the infected are of the koi’s body. Though these parasites can affect the skin they will also infect the gills of your koi as well.

      Treatment: There are treatment options for costia. Malachite green and formalin can be used but you will need to make sure there is no salt in the pond to start with. As with flukes, potassium permanganate can be used to treat costia. Some practitioners will recommend a strong salt bath almost equivalent to that of ocean strength salt concentrations (around 3%). Other treatments include trypaflavine which goes by the trade name Acriflavine and copper. Copper is used because most invertebrates, like costia flagellates, have copper based blood (hemolymph) and therefore copper as a treatment in ponds is toxic to them. Acriflavine should be added to your pond at a rate of 1ml/liter and copper is most appropriate at 2 mg/liter. It is critical that you do not overdose with these two treatments.”

      Costia usually takes the form of small red bumps, not sure how large or what color your koi’s bumps are presently. Having not seen it I would lean towards a fungal infection. Sorry I can’t be more help

  24. Bill Gorton says:

    I noticed last week that one of my fish had disappeared. I suspected a raccoon. However today I noticed a fish swimming a little funny. Kind of off to the side with a twist. There are 8 fish in an outdoor pond. The rest seem find and they are breeding so I figure they are pretty happy. Dont do much to the pond water but filter an airate. If I add water I declorinat. They have all seemed pretty content for years. First sugn of and issue. What could this problem be?

    • Koi-Care staff says:

      Your fish could certainly have had a run in with a raccoon-the animal could have injured your fish in an attempt to snag it from the water and now your fish is swimming irregularly because of it. If your water quality doesn’t show anything unusual then it may just be something like what I suggested above that is affecting only one of your fish. It may be a wait and see kind of thing.

  25. Pat Keller says:

    I have some black koi, several have a white smooth patches on head & body. Looks like scabs. Several have had these for several years No problems swimming or eating Pond people who clean my pond every year said to use salt treatments but that did nothing Do you have any idea what it is and how to get rid of it? Thank you

    • Koi-Care staff says:

      Pat, this sounds most likely like Carp Pox which is a herpes virus. This is pretty common among these fish and really shouldn’t be a health issue to your fish unless their growth causes them to have trouble feeding (by growing in or around their mouth). There’s no real treatment for carp pox but typically raising the water to above 60 degrees will help regress the virus a bit. Carp Pox is usually something that becomes more pronounced during that seasonal shift to winter as dropping water temps tend to spark the herpes virus activity and growth.

  26. Pat Keller says:

    Thanks for answering my question cause no one else had any ideas what it is. One more question about carp pox, will it spread to my other fish? One again thank you so much.

    • Koi-Care staff says:

      Yes, it can spread so if you really don’t want others afflicted you may want to quarantine or cull those fish with the pox. As I said before though, its not the worst thing koi can have and they can live fine with it. Young koi juveniles are actually more susceptible to it and can suffer mortality because of it.

  27. Kaitlin Johnson says:

    We have an outdoor pond that contained three adult koi and around twenty baby fish. Most of the babies have died and our two biggest fish have also. We have checked the water multiple times and it seems fine but when the fish die they have white cotton-like substance on them. They were found by our water fall and we do not know if that is caused by a disease or if the white substance is just the fish decomposing. We could really use help to save the remainder of our fish.

    • Koi-Care staff says:

      It sounds possibly like it may be fungal in nature. This an excerpt is from my site:

      Fungal infections in fish almost always begin externally and start through a break in the outer skin layer of the fish. Affected Koi usually display fluffy or cotton-like growths on their skin. These growths may also exhibit a green tinge because of algae growth on the fungus. There may also be raised white, brown, yellow or green irregular bumps seen on the fish’s fins. Most infections can be successfully treated if caught early so it is important to visually inspect your fish frequently.

      Melafix and an addition of some salt to your pond may be in order. How do your other fish look?

  28. James Hathaway says:

    I have a mixed breed small pond in my backyard koi, black moor, fan tail, a channel catfish, and tadpoles. Recently my black moor developed one white spot just behind the gill but behaves normal as do the other fish. This spot is about 2mm in diameter. Im unable to diagnose the problem myself and would greatly appreciate any help. I love my fish and would hate to lose any. I do live in Colorado so my water temperature is low and I have not fed my fish as a result if that helps. Please advise on possible causes and treatment thank you.

    • Koi-Care staff says:

      It sounds fungal to me. This is an excerpt from my site regarding fungus.

      “Fungus can be removed by gently rubbing the area with a cotton swab while the infected area must be treated with an antibiotic or antimicrobial cream immediately afterwards.”

      White spots could be several things though such as Trichodina which is a parasite as is White Spot. Cotton Wool disease is another ailment that causes white on the body -its fungal in nature. I would quarantine this fish and do the treatment described above. You can also treat fungus using something containing malachite green like Proform C.

  29. Annette says:

    one of my koi fish that is a male,looks like it is full of eggs,he is blown up and struggle to come up for food,please help

    • Koi-Care staff says:

      there are a few possibilities going on here. 1) you may be overfeeding your koi and therefore your bloated koi simply has excess weight gain. 2) you have an excess of harmful bacteria in your water and your bloated koi has internal bacterial infection that is causing the bloating. 3) the koi you think is a male is actually a female and full of eggs. If you are feeding like 3 times a day I would reduce that for sure. Otherwise I would check your water chemistry and make sure your levels aren’t off

  30. Jacqui says:

    I just took a close look at my koi since the harsh winter and noticed that one of the butterfly koi has some kind of growth coming out of his mouth. Kind of looks like a bubble of tissue. Looks fine otherwise . Any ideas? They haven’t begun eating yet for the spring. Thanks.

    • Koi-Care staff says:

      What you’re describing sounds like it could be mouth rot. Below is an excerpt from my site regarding the subject:

      Mouth rot is a symptom of something larger and that is usually poor water quality that is causing your fish’s health to be compromised and open to infection. You’re going to want to stop feeding for the time being and start improving your water quality by doing a 30% water change. Next thing would be a light salt bath treatment and perhaps a treatment of Mela-Fix. You will also want to monitor your water quality by testing it regularly. You can also remove the fish and treat the sores with hydrogen peroxide or iodine.

  31. maple says:

    several of my 40 koi which were all born in this 2,000gal pond a few years ago have developed blister like structures on the heads and bodies…one last summer had such a grotesque flowery growth on its head that my granddaughter nicknamed it flower…these growths do continue to grow in size…all are acting normal..as I took the one with the large flower out of the pond by net, the blisters easily ruptured while in the net…no ulcer was noticed where the growth was…I would appreciate some advice …thanks

    • Koi-Care staff says:

      My best guess here would be carp pox. Because your fish are doing well otherwise and carp pox usually shows up when there is a drop in pond temps (fall) or a rise in pond temps (spring) I would be confident is saying that is what it is. Its a herpes virus and there is no cure -your fish will always have it to some degree but it should lessen as you get into summer and temps are more steady and high. I don’t recommend cutting them off as this may spread the virus and open the fish to lesions and infection.
      good luck , Koi-Care

  32. Jade says:

    Hi I have a white koi carp about a year old and I gone out today to feed them and this one fish is upside down in bottom of pond still alive it nt eating and all it’s belly has gone a pinky red colour am not sure on what to do or if it’s ill any help would be great full thank you

    • Koi-Care staff says:

      the first thing you should consider is getting this fish in a quarantine tank and adding a bit of salt. Salt will help in a couple different ways including making conditions more difficult for some viruses and bacteria to do well in and making it osmotically easier on the fish. You will also want to feed you fish some frozen peas. It appears that your fish may have a swim bladder disorder and it may be caused by a virus or bacteria -its tough to say for sure with swim bladder issues. Make sure the quarantine tank is sufficiently aerated.
      hope this helps, Koi-Care

  33. reina says:

    My fish suddenly bloated.. His scales seemed tto soften and the opening of his gills seemed to have curled.. What do i do? Thankyou

    • Koi-Care staff says:

      this is a bacterial induced disease called dropsy and is associated with spring and rising water temperatures. One treatment you can put into play is injection of antibiotics and putting the fish in quarantine. There is most likely severe kidney damage already so there isn’t a great chance of survival at this stage.

  34. danny says:

    Can I use melafix when my pond has salt with .4 ?

    • Koi-Care staff says:

      Yes, you certainly can. I’ve used it with salt water fish in a saltwater aquarium with a lot of success.

  35. Jenny Zeller says:

    I have a koi that is bent. It looks like it just stays in one spot but it doesn’t. I don’t think it can swim normally but it doesn’t move when I try to get it to move. I tried to hand feed it but it only took one stick then wouldn’t open it’s mouth again. Do you know how to help me? Thank you.

    • Koi-Care staff says:

      It is difficult to assess without seeing it in person but I’m assuming that this bent appearance began recently (i.e. it hasn’t been this way since it was a fry). So if this is a newer thing then there are a few explanations possible; 1) electrical leak in your pond from something a submerged pump 2) air bladder problems 3) internal tumor 4) vitamin C (ascorbic acid) deficiency causing scoliosis and/or low quality food causing scoliosis. Electrical leak is unlikely but the others are all possible though I would put my money on the Vitamin C deficiency and if that is the case you can reverse it over time by increasing the Vit. C in this fish’s diet. Sorry I can’t be more help.

  36. Kim says:

    Hi, I have a 6500 gallon koi pond. Three days ago I noticed my biggest koi was resting on the bottom and not eating. She was fine and eating the day before. We had a blue heron hanging around so I thought she was scared. We were told to add a little salt to decrease her stress. Well yesterday, we noticed her gills were a little swollen and the sides of her face discolored. We brought the salt up another 0.1%. We did that again today. It is now up to 0.3%. I was suspecting some sort of gill parasite. Today, after we added the salt, she seems to be swimming around more. I know that she is probably irritated by what is going on and the salt. I will I know if this is working. Is her swimming around showing she is getting better?? I was told to continue and increase the salt to 0.6 to make sure the parasite or bacteria is killed. Is that true?? I really do not want to lose this fish!!

    • Koi-Care staff says:

      0.5 to 0.6 is acceptable and should take care of gill flukes if that is the case with your fish. Salt additions to your pond act as an osmotic relief to fish and will result in more slime coat which is a koi’s first line of defense, so to speak. Just remember that you don’t want to keep your pond salty year round as you may end up with parasites that, over generations, will become more salt tolerant. yes, if you fish is starting to swim around more then it is undoubtedly doing better. You can also try feeding your koi “Medi-Koi” as a precaution as well. The other thing to keep in mind is that to bring your salinity back down you will need to do water changes because salt won’t evaporate (sounds obvious but many people don’t think of that).

  37. Ravi Don says:

    I have a koi with thin appearance. It looks like it just stays bottom of the tank and difficult to breath. Sometimes it tries to swim then falling sideways & looks so stressful. Not eating for few days.I want to save my Koi.

    Please help!

    • Koi-Care staff says:

      As with many illnesses that can’t be diagnosed right away its always a good idea to quarantine your fish in a separate place, add a little salt to the water and some melafix. It could be that your fish is suffering from something stress related like harassment from other fish or perhaps it has a bacterial infection internally or externally somewhere. If its having trouble respiring then you may have high ammonia levels in your tank which would cause a cascade of health problems with your fish. So after you quarantine I would check water chemistry in your pond -most often your fish’s health problems will stem from there.

  38. Ravi Don says:

    Hi koi Care,
    Thank you for your prompt response. This fish is not eating any food for more than a week. Any suggestion for a vitamin or liquid food I can dissolve in the water. This fish is approximately 8cm long.

    Thanks!!!

    • Koi-Care staff says:

      well if its internal and bacterial in nature then salt and melafix will help. if you can get the fish to eat try Medi-koi. Otherwise you may have to do antibacterial injections. You could actually try koi clay to add to the water since koi love it so much but honestly I don’t know if that will help.
      sorry i can’t be of more assistance

  39. Tom says:

    We have a 12 – 14″ koi that has developed what looks like a tumor on it’s left side behind it’s gill. We have had this fish for several years in an outdoor pond (Long Island, NY) with about 8 other fish (koi & goldfish). It seems to be very fast growing, noticed it yesterday & it is much bigger today. Other than this growth, the fish appears to be fine, eating & swimming normally. What could this be & should we separate it from the other fish?

    • Koi-Care staff says:

      Tumors can be malignant or benign so you may be able to leave this fish as is without any further problems however if its malignant or grows big enough to hinder the fish then that is when you will want to consider having it removed. If you have it removed that is when you will want to quarantine the fish and treat the water with something like melafix so that there aren’t subsequent infections at the surgery site post removal.

  40. Jacky says:

    Hey,I have 15 koi fish now,I don’t know it is from where and I bought few yesterday…however I go near them,I found them not so hyper and kept their self under it.only when I feed they will come out??can I know why???and I had a koi fish almost 6 month I rare it,after I mixed them with the fish,the 6 month year koi doesn’t active and look dead,,I rare them in aquarium..quick big and those koi are still small,not so big but maybe around our middle finger length,can I know why happened??and what is the treatment???if u put those general aid chlorine into it,6-7 drop,will they die as well or can’t take it??

    • Koi-Care staff says:

      They may be scared to come out because there may be a bird or another animal that is trying to eat them when you are not around so they are scared to come out.

  41. l.shaw says:

    I have a golden koi which appears to have white wisps behind its gills. It is active and feeding well but from time to time it lies at the top of the pond on its side.I have isolated it and used pond salt and mela-fix. Can anyone advise?

    • Koi-Care staff says:

      the following is from my website:

      Anchor worm, also known as Lernea is a crustacean parasite that attaches to, and digs into the skin of fish. The female Lernea attaches to fish while males do not. The worm feeds on the fish, damaging its tissue. This leads to a bacterial and/or fungal infection on the fish. Another crustacean parasite, Argulus also attaches itself to fish and causes damage to tissue. Argulus have eight legs and rounded bodies. They also have to big suckers which are used to attach to the fish. Their appearance leads to their nickname, fish lice. These parasites can cause considerable irritation to fish and can lead to bacterial infections.

      Treating Anchor Worm: They can be removed using tweezers or other small pincers. After removal, rub some Neosporin on the infected area. Use Dimilin or Dylox to treat the pond.

      From your description it sounds like Anchor worm.

      good luck

  42. Betsy says:

    Hi everyone.
    Have a question that no one, including “dr. Google”, can answer.
    I have a fantail about 12-14 inches long who suddenly began to segregate herself from the rest of the gang in the 6,000 gal. pond.
    I watched her a couple of days and saw that she couldn’t reach the surface with out EXTREME struggle. She was never laying over.
    I set up a QT, (150 g.), and have been cleaning it daily.
    Here’s the question.. when I caught her and really checked her over there was nothing in her mouth, or gills, no signs of any parasites at all, no sign of disease, BUT her spine is SEVERLY curved?? She has never been that way and none of the others are either.
    I had checked for injury, nothing obvious.
    I am ASSUMING its scoliosis. I have been heating, cleaning, salting, aerating and feeding her medikoi. I also decided to add powdered pure Vit. C to her water.
    I realize that could crash the PH but have checked it…all ok.
    Has scoliosis ever been reversed? She has been pooping up a storm, so she is eating. I am considering putting her back in with everyone else but watching the poor thing struggle to get to the surface to eat and having no coordination to do so is cruel.
    Does ANYBODY have any ideas to try, or is scoliosis irreversible!
    THANK YOU, THANK YOU, THANK YOU!!!

    • Koi-Care staff says:

      So if this is a newer thing then there are a few explanations possible; 1) electrical leak in your pond from something like a submerged pump 2) air bladder issues 3) internal tumor 4) vitamin C (ascorbic acid) deficiency causing scoliosis and/or low quality food causing scoliosis. Electrical leak is unlikely but the others are all possible though I would put my money on the Vitamin C deficiency and if that is the case you can reverse it over time by increasing the Vit. C in this fish’s diet (I don’t think adding it to the water will be as effective as feeding the fish something with vit. C added). If you need to get a certain food to your fish on the bottom you can always attach it to a rock or something heavy. So for example you could attach a yellow bell pepper to a rock with cordage or zip tie or something similar and send it to the bottom. Another veg. High in ascorbic acid is kale and that can easily be delivered to the bottom.
      Sorry I can’t be more help.
      -Grant

  43. Cy Burman says:

    Dear Sir,

    I have written once before, but I have further observations that may give you a further clue as what the disease my koi carp carries.

    There seems to be a mucus covering most of the body which has made identification a problem. There is no sign of an injury or of the fish scratching itself, although the scales do seem slightly raised. There is yet no sign of pop eyes, but I have noticed thick white lumps on the tail of differing sizes ( NO FIN/TAIL ROT ). It’s fins are kept in, causing a slight abnormality to the normal swimming pattern. The body is slightly thin and it stays close to a water fall, presumably for oxygen. When it is not by the fall it stays at the top but is not gulping for air as expected. I have not observed if its feeding properly except I must say I haven’t seen it feed. There are two other koi in the pond which so far do not seem affected.

    I hope this helps.

    Regards

    C R C Burman

    • Koi-Care staff says:

      Cyril, this is an excerpt from my site:

      Your Koi fish may have Lymphocystis, also known as Carp Pox if it has any buff discoloration on its skin. Another sign of Lymphocystis is shiny, greasy looking skin. This condition occurs when the water temperature in the fish’s environment has changed. Lymphocystis and Epistylis look alike, but they each respond differently when salt is added to the fish’s environment. Carefully watch the fish for a week after adding salt. If you still notice the symptoms mentioned above, then the fish is suffering from Epistylis. Epistylis is an uncommon parasitic infection that is dangerous and can cause other diseases and ulcers in your Koi. It is usually caused by poor management of the water, resulting in dirty water infected with parasites. If you do not regularly change the water in the pond, it can easily become a host to these parasites. Epistylis looks like a fungus and thrives in ulcers and wounds on Koi fish. You can identify an infected fish if you see white colored tufts in and around ulcers and wounds on the fish’s skin. Change the water in the pond and add salt to combat these parasites.

      If its epistylis you can also treat with formalin-based solutions.
      Carp pox has been known about in the koi world for over 400 years so its definitely not new but unfortunately this herpes virus is chronic though not necessarily life threatening. Clamped fins is typically a result of stress. Raising the water to over 60 degress F will help if its carp pox. Viral afflictions can be difficult to diagnose as a general rule, a lot of the symptoms are similar.

  44. Jeff Vando says:

    I have lost 2 KOI and a third one is showing the same symptoms, They developed a red spot on their bodies in the same place, right side of body right below the dorsal fin. I tested the water, PH=6.5, ammonia=0.25, nitrite=0 and phosphate = 10. I was told these reading were OK yet my fish are still dying. I am a novice at owning KOI, they came with my house when I bought it. Any help and suggestions would be appreciated.

    • Koi-Care staff says:

      Hi Jeff, sorry for the delayed response. You could get away with at pH of 6.5 but between 6.8 and 8.2 would be better. Remember that the pH scale is logarithmic so any small swings are a big deal. Ammonia really should be zero and your nitrite looks good. It sounds like your koi may be experiencing ulcers on their bodies and ulcers are typically a sign that something larger is going on. Ulcers are often caused by parasites that get on the skin and through invasive parasitic action expose the area to bacterial infection and ulcers. What you can do is feed with Medi-Koi and try to treat the external bacterial infection with Mela-Fix.

  45. jim says:

    15 plus year old large Koi, one of about 8 but the only obviously sick one. has lost a lot of weigh/size and body is now bent, curved, appears to be very sick or dying?

    • Koi-Care staff says:

      Sounds to me like your fish has some degree of scoliosis which is most likely due to a lack a vitamin C in its diet. Try attaching something high in vit. c like kale or green bell peppers to a weight and put it in the pond. You could also quarantine the fish and feed the same -that way you could be sure the afflicted fish is eating.
      -grant

  46. Abi says:

    I have a Koi that’s suddenly floating on the surface, its tail is swollen and almost pineconing but not all over the body, with what looks like a slight mucus, and it is keeping the fish from swimming properly, its rectum seems also very large and swollen out, PLEASE HELP!

    • Koi-Care staff says:

      that sounds like an internal infection of some decription. You need to quarantine this fish and feed with medi-koi or something similar & add a little mela-fix (in the event that you also have external infection) to the water as well as some salt. You may need to do anti-bacterial injections as well but you will need to call someone in to do that.
      -Grant

  47. leon says:

    Hi. I have two mature (6 years old) laying on their sides at bottom of pond. But they do still swim normally around most of the time. It is winter in South Africa. Please advice.

    • Koi-Care staff says:

      could be a lot of explanations for this behavior. What kind of water temps are you seeing? how are they eating? is your water chemistry in good shape?

  48. Gary says:

    Hello,

    I have notice today that one of my largest black carps has developed white fluffy, cotton wool like spots all over his body. He also looks like he is gulping for air sometimes. I cleaned the entire pond water out a few months ago and regularly was the filter foam out. What can I do to treat him?

    • Koi-Care staff says:

      Definitely sounds like columnaris or cotton wool disease. You can treat the water with potassium permanganate. The gulping for air sounds like the fungus has made its way to the gills hence the labored respiration. You can remove the fungus on the body with cotton swabs and an antibiotic cream to follow. You may also want to consider antibiotic injections for the fish as well.
      -grant

      • Gary says:

        Thanks for the reply. Before your response I went to my local pet store and I bought Blagdon Anti Fungus and Bacteria treatment. It’s a combination of Acriflavine Hydrochloride and Malchite Green Oxalate. It’s a five day course and the cotton wool like growths have definitely reduced so far.

        The back of the packaging says this product is safe for wildlife using the pond, I suppose including my dog! I’ve read that MG is a carcinogenic, does this apply to the oxalate variety too? My dog likes to drink out of the pond and I’m not sure how long after treatment it is safe for him to drink from it again. Do you know much about this sort of product?

  49. Kacee says:

    We moved into a house with a very small pond (maybe 2-3 feet across by 3-4 feet wide and a few feet deep) a couple months ago. It has 4 smaller Koi (about 5-6″ long). Came home today and two were dead, the other two look like they’re in bad shape. They will get close to the surface and look like they’re almost gasping. Any idea how to save the two??? I feel terrible. I know there is an algae problem. There is a pump. The previous owner left some algae cleaning stuff that says it’s safe for fish. We’ve used on occasion, but not too much. Now I’m afraid I poisoned the fish. Can they be saved? Do I try to take them out of the pond in a bucket or something? If so, what temperature of water? It’s been in the high 90s outside.

    • Koi-Care staff says:

      You didn’t poison the fish but they appear to be swimming in water with poor chemistry. If you have bad algae you most likely have excessive ammonia and/or nitrites. This will essentially burn the gills of your fish and cause them to gasp. Antother thing is that you may not have adequate aeration and this is especially a problem in a small pond with high temps. Hot water doesn’t hold as much dissolved oxygen so you need to make sure you have air stones or something similar. you can certainly try to save the remainder by putting them in quarantine and dealing with the water quality of the main pond.

  50. gardner says:

    My Koi have a discolored skin and mouth opens like a parachute ?

  51. Curt says:

    I have a 2400 gallon pond with 15 Koi (1) 16″ (1) 12″and the rest 4-6″
    A couple of weeks ago I noticed the largest Koi has reddish / pink on the tail and then some ulcers on the tail. I did a some homework and assumed it was tail rot and started treating the whole pond with Melafix. After a treatments of 12 oz. for a week it appeared the reddish pink improved but the ulcers were still on the tail. I increased the Melafix to 16 oz. for another week and with no improvement.I also got the salt level up to .1 I now have the Koi in a separate tank with aeration only, no filtration.I am now using Melafix and Pimafix and am utilizing pond the pond water and doing a 50% water change daily just before dosing with the Melafix and Pima fix. The koi is eating and was eating like a pig when he was in the pond. I think I was over feeding the pond and this is what possibly caused the problem. All the other fish seem fine and active. The pump is moving about 4500 gph. The water appears to be good with minimal algae,(enough for the fish to eat) 25%water Lilly coverage. I do need to get a water sample to a local pond shop for analysis. Thanks so very much for your help, I am desperate. Not only to I want to cure the Koi but want to figure out what is the possible problem in the Pond that had been so perfect and almost maintenance free for years.
    Thanks Curt

    • Koi-Care staff says:

      The melafix is a good plan as are water changes but I would definitely quarantine your fish -its so much easier to treat and you can be sure that it is eating any special foods that you give like Medi Koi (which you may want to look into starting). You may have high ammonia but the signs are typically fish gasping at the surface and clamped fins. You may have some water quality issues though that are allowing for the bacteria to cause the observed fin damage so I would consider a boost to your filter media by adding something like “Microbe Lift” -this will supercharge your beneficial bacteria loads and help remove excess nutrients in your pond that result from overfeeding etc. Also, you can bring the salt up to 0.5 to 0.6 -there is a theory that over the time and generations of bacteria, they have become less affected by salt and therefore higher levels are needed to kill them. Just remember that if you do whole pond treatement that salt doesn’t go away unless you do water changes following treatment. Ideally, if you do a quarantine with higher salt, melafix and medi koi and do a whole pond treatment with microbe lift you should be in good shape.
      Hope this helps, Grant

  52. Roberta says:

    My Koi has red spot on the fin and the tail.
    What should I do?
    Thank you.
    Roberta

    • Koi-Care staff says:

      Roberta,
      You need to quarantine your fish, first off. Then increase the salt concentration to 0.5%. You will want to treat the water with mela-fix. Make sure your quarantine has good aeration and filtration. Your pond water probably has an increase in excess nutrients that allow bacteria, like the one most likely causing the red spots, to thrive. You will want to test your pond water on a regular basis and watch for ammonia, nitrites, nitrates. You can even do something like microbe-lift to boost your beneficial bacteria load in your filter media.
      Good luck, Grant

  53. Adrian says:

    My Koi keep spinning in the pond…I quarantine her and add salt, green and blue medi and heater to 30 deg with oxygen… but seems like nothing much better… She still keep spinning.

    • Koi-Care staff says:

      My best guess would be parasites -they are perhaps bothered by them and/or trying to scrape them off. You may also want to check your water chemistry to see if anything is out of line.

  54. sindy says:

    i hav som small coi fishes in an aquariam in my living room.when i buy them they stay alive for about 1 week and then they start dying out.they start to swim upside down then swim with extra speed then start hittin on the aquariam.then they die cud someone please help me out here.

  55. Koi-Care staff says:

    Sounds like your water chemistry is bad. You may have an excess of ammonia. Start with the water chemistry -test it or have it tested. Make sure your filter is appropriate for the size tank you have and that it has plenty of beneficial bacteria on it.

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