Aquatic Plants for Your Koi Pond: Why They’re Important and How to Choose the Right Ones

Adding plant life to a koi pond helps improve pond life for koi, as well as adding beauty to the pond itself.

Koi owners need to make sure they select the right aquatic plants that will harmoniously co-exist with their koi. They also need to ensure that their plant placement is done properly as well as not planting vegetation that will just be eaten by the koi!

 The benefits of including aquatic plants in a koi pond

Aquatic plants are considered an excellent addition to any koi pond. Aquatic plants, in fact, help increase oxygen production in the water, helping to keep the pond properly aerated for koi. Their presence also helps keep the water cool by providing shade to the koi. Additionally, around the spring breeding season submerged plants act as a critical surface onto which female koi attach their fertilized eggs.


The presence of plants also prevents the spread of algae from getting out of control. The shade plants provide reduces incoming light into the pond and therefore limits photosynthesis of algae. Their natural ‘filtration’ system prevents blanket weeds (string algae) from forming, mainly through absorbing harmful nitrates that lead to their formation in the first place.

 Tips for introducing koi to plant life

The best way to introduce plants into a koi pond is building a plant shelf. This shelf can be built along the edge of the pond itself. It’s a container where water plants are suitable for planting. It’s a good idea to weigh down the plants with large rocks or stone to form a barrier between the base of the  plants and koi, preventing the risk of the koi eating the plants. Pond owners should be aware that predators like raccoons may use the shelves as a tool for feeding on your koi. For more on how to prevent pond predation see this article.


A vegetative filter may be an alternative to introducing aquatic plants to your pond. In this system the plants are grown in a separate containment area that connects to the main pond. The plants here can serve as a natural filtration system as water from the main pond travels in and out of the contained area. This gives you all the filtration benefits of having aquatic plants without the risk of your pond plants being eaten or dislodged.


Of course, you can always place aquatic plants directly into the pond itself. There are several options to choose from when deciding on which aquatic plants to put in your pond.   Pond plants can be divided into 3 main categories that are discussed below:

1)      Floating plants

2)      Shallow-water marsh plants

3)      Submerged plants


1)      Floating Plants

This type of pond plant can be truly free floating with its main vegetation on the surface while the roots hang down, unattached or there are types where the roots are attached to the muddy bottom. The benefits are that they are easy to care for, they provide plenty of shade for koi and they compete with algae for nutrients as well as blocking light that would have otherwise helped algae to grow, all of which greatly reduces algal growth.  Additionally, they remove a lot of the existing nitrogen and phosphates in the water and thereby do a great job of filtering the water. 


Water Hyacinth

Some popular choices for floating plants are water hyacinth.  This species is an annual in the colder regions of North America but a perennial in the warmer parts of the States.  They bear purple or blue flowers and their roots form a compact “nest” beneath them.  These plants do a great job of filtering the water of excess nutrients. 

water hyacinth in koi pond

Water Hyacinth

Water Lettuce

Another free floating plant is water lettuce.  This is more of a tropics/warm climate plant and forms compact leaf clusters on the surface with a compact root mass forming beneath the plant.


Water Lettuce in a koi pond

Water Lettuce


Water Lilies

When it comes to floating plants with attached roots water lilies are definitely the most popular choice amongst koi pond owners and may be the top choice of any of the aquatic plants.  These plants will do well in just about any region of North America in any season and can be potted and placed at the bottom of the pond.  On the surface, pond owners with water lilies will find a pleasant array of leafy covering and beautiful flowers that will nicely accent any pond.


Water lily in a koi pond

Water Lily



Looking similar to water lilies the lotus is one of the oldest cultivated aquatic plants and make a great addition to any koi pond.  Their leaves are typically very large, as much as 18 inches across which is great for providing shade to your koi in the summer.  Often confused with water lilies the lotus flower is very beautiful and also fragrant.  A word of caution should be noted here as these plants have a substantial growth rate and are best planted in larger koi ponds. 


Lotus in koi pond



Water Poppy

Water poppies produce small oval leaves and yellow flowers and are a great choice for koi ponds.  They grow fairly quickly in summer and add a nice touch of yellow to your pond while filtering the water.


water poppy in a koi pond

Water Poppy


2)      Shallow Water Marsh Plants

These type of aquatic plants are typically planted on the edge of your koi pond in the shallows.  They are usually very lush and do best in only several inches of water.


Umbrella Plants

These tropical region aquatic plants do well in shallow water and for those living in colder climates they need to be brought in during winter.  Umbrella plants, as the name suggests, have umbrella-shaped leaves at the end of long stalks.


umbrella plant in a koi pond

Umbrella Plant


Water Iris

A favorite amongst koi pond owners the water iris comes in several different species.  They have long, sharp leaves and depending on the species may produce flowers in colors ranging from blue, white or yellow.  These plants are typically planted in pots that are then submerged.  Most iris will do great both in full sun or partial shade which is nice for those with a lot of tree cover nearby.

water iris in a koi pond

Water Iris


This plant produces a slender green stem and is fast growing.  It is best placed on the peripheral parts of your pond and will do great in partial shade.


horsetail in a koi pond



3)      Submerged Plants


Suberged plants are usually grown in pots then placed at the bottom of a koi pond.  Referred to as oxygenating plants this class of aquatic plants do a great job of removing excess nutrients from the water such as nitrites as well as CO2 and add oxygen to the water.  One word of caution though, these plants are often uprooted and eaten by grazing koi so care must be taken to protect them.



This submerged plant is a fast growing oxygenator and requires a good deal of light. These plants can grow up to an inch per day and can be propagated using cuttings.


fanwort in a koi pond



American Waterweed (Elodea)

These plants do well with pond substrates that are silty.  They are completely submerged with the exception of small white flowers that bloom at the surface.  It is great at utilizing the dissolved CO2 in the water and providing cover for fish, especially small koi.  Sometimes the leafy stalks will break off and float away to take root in another part of the pond.  They do very well in milder climates.


elodea in a koi pond



Water Purslane (Ludwigia)

There are many species in the Ludwigia family but Red Ludwigia is a good choice for your pond as this plant grows fast and is a great oxygenator.  It can be planted as a submerged addition to your pond or you can let it float.  They produce small flowers and their leaves are a reddish or purple color.  They typically do well in a lot of direct light.

water purslane in a koi pond

Water Purslane

This entry was posted in Aquatic Plants and tagged aquatics plants, koi eggs, koi ponds, oxygenators, shade plants, water filtration, water quality. Bookmark the permalink.

21 Responses to Aquatic Plants for Your Koi Pond: Why They’re Important and How to Choose the Right Ones

  1. I have a large pond with large koi in it. Every spring it gets a green alge & cant see the koi. We have cleaned all the filters and still isnt getting clear. What is the best thing to do to solve this problem?

    Thank You,

    • Koi-Care staff says:

      This occurrence is typical of spring time and rising water temps and longer sunny days. The condition is sometimes referred to as “green water”.
      Green water which is essentially single celled algae is often associated with spring and summer as that is when ponds begin to experience increases in sunlight and water temps.- both important elements for algal growth. However, another element that aids in algal growth is nutrients such as nitrates. So right off the bat check your water chemistry and make sure you’re not feeding to excess which can result in higher nitrate levels. There are chemicals out there as you’ve discovered that will help to mitigate for green water and those include a products like AlgaeFix and Accu Clear. To really get at the heart of the problem though your water chemistry comes first and after that the next best approach is an in-line UV light as part of your filtration system. UV is a very effective control for algae and doesn’t involve chemicals that have the potential to complicate things.
      Hope this helps

  2. What salinity level do you recommend for koi ponds with plants?
    Thanks- Rodger McPherson

    • Koi-Care staff says:

      Rodger, that answer will depend on what type of plants you have in your pond. Some plants have higher tolerances than others, some have lower. As far as koi tolerance goes here is an excerpt from my site:
      The use of salt in koi ponds has, for long time, been a tried and true method to deal with various water quality and health problems that arise. Some of the benefits of salt is that its a cheap way to keep some disease at bay, control algae and may also lower nitrite toxicity. Additionally, salt plays a part in the osmotic pressure between the fish and the outside aquatic environment. There is a differential between the solute concentration of the fish’s blood and the fresh water that it swims in so the addition of salt actually lowers that concentration differential and makes it easier on the fish by reducing the amount of work its body has to do. A salinity of up to 5 ppt (parts per thousand) or 0.5 % is acceptable.

  3. pondman says:

    I have noticed that my pond as gone green and my filtering system is in good nick ive tryed algo rem and it not done anything what else can I do please let me know thanks

    • Koi-Care staff says:

      I have a new article about algae blooms with a section on green water -here is the link it will have lots of good solutions for your green water issue.

  4. lovemykoi says:

    For years I’ve had water hyacinths in my koi pond and they’ve been so healthy and prolific that I’ve given them away by the trash bag full. This year they look awful,they are yellow and brown and burnt looking, have had NO flowers and the roots being eaten by the koi. The only difference is that I bought two butterfly koi last spring and added them to my pond. Are they more voracious? Is that why my water hyacinths are being eaten? Have they taught all the others to eat the roots?

    • Koi-Care staff says:

      Hi, well for starters, and like i advise many pond owners, is to check water chemistry. If, for example, your pH is high you can experience what you have going on with your hyacinth. Your problem probably doesn not stem from the roots being eaten but it may stem from the new fish. There is a possibility that your new fish, if not properly quarantined prior to letting them into your pond, may have brought in a disease that is affecting your hyacinth. I would be more inclined to lean towards a water chemistry issue though. Is there anything else that has changed? Like the weather? More hot this year than last?

      Thanks for responding so quickly.
      It’s spring water, just like it’s always been. When I take some hyacinths out and put them in a barrel with no fish or in with my goldfish, the color returns and and the roots grow long.
      I bought the two new butterfly koi from the same pond and garden store where I’ve bought all my fish. They do quarantine their fish before selling them.
      The only thing different this year is the two butterfly koi and the hyacinths with hardly any roots at all. Are butterfly koi more likely to eat the hyacinths than regular koi?
      I’ve heard that you can make things that float with netting on the bottom that you put the plants in so the fish won’t eat the roots. So you know how to make one of these? Or do you know where I could find out how to make one or more of these?

      Given your barrel test it sounds like it is indeed your new butterfly koi (unless you have some other fish or pests that entered the system recently that are eating the roots). I don’t know butterfly koi to be particularly fond of roots or have a larger than normal appetite but your new koi may very well have a taste for it. The only other thing different with the butterfly koi is the propensity for mechanical fin damage (splitting). I assume you used the same pond water for your barrel experiment? As far as the floating netting goes I have heard of it but never seen anyone need to do it personally. I imagine it would be some pretty small mesh netting attached to a circular float ( a modified pool noodle perhaps) and weighted at the bottom.I found this on Foster and Smith (
      good luck

  5. Scott Guerra says:

    I introduced for the first time, water lettuce to my fish pond. I was thrilled on how it multiplied and covered the pond to protect the temperature of the water as well as adding oxygen to the water. Winter will be here soon. Do I leave these plants in…or take them out. If I take them out, how soon should I do this? Thanks for your time, Scott PA

    • Koi-Care staff says:

      Water lettuce needs to go. As far as timing of removal you want to do it before they get damaged by frost. The nice thing is, and as you’ve discovered, they multiply pretty readily so when it warms up again you can get a whole new batch going.

  6. Robin says:

    My Koi are hiding! My water is filtered, the water is clear, and the temperature is about 55 to 58 degrees.
    Last year four of the Koi were trapped by raccoons who climbed into my small pond, and feasted on my fish. I replaced the Kopi with fish that had overwintered in the pond of the garden center.
    This year I put in milk boxes so that the Koi would have a safe place to hide. they do not seem to come to the surface, and eat only a portion of the food I give them. They move very slowly, and do not come from under the milk box and swim.
    Should I wait for warmer temperatures, and the floating water plant to cover the surface? Is this normal behaviour; Do Koi prefer to lie still and gather in pods?
    Do I need to wait for later in the season, and but more active fish?
    I appreciate any response.
    Robin of Long Island, New York

    • Koi-Care staff says:

      Certainly if you water is still cold they will not be as active but if they have been molested in the past by wading birds or raccoons then I am not surprised that they are shy. They may still be getting “night visitors” by various animals but you may not realize it. Give it some time though and you should see some more activity as the water warms.

  7. Carol Smith says:

    I have a very small pond with 7 fish. The pond is about the size of a small car but not more than 18 inches deep at the deepest part. Years ago I put 3 potted water lillys in it. Some still bloom but there is now a huge amount of dirt and weeds and peppermint plants growing out of all the dirt. It looks awful. I am having someone come and clean the pond out this weekend. My fish need some shade. Is there any kind of plant that will help protect them that won’t take over the pond and get all messy and ugly? I live in Indiana, so very cold winters.

  8. Janet Schuler says:

    We have two 5-year-old koi residing for the first time in a 150 gal cattle feeder under an alder tree. They have a bio filter with a strong waterfall. Last spring we added floating plants and four potted plants. Everything thrived during this past hot summer on the California coast. With winter on its way, the plants have overgrown and there’s little sunshine hitting the water. I recently read that potted plants can steal oxygen during the winter (and we do generally get under 1en days of frost here). My question is, have we over planted this temporary pond, and how can we ensure the fish get enough oxygen and warmth?

    • Koi-Care staff says:

      I don’t know about plant’s winter time use of oxygen but certainly they use oxygen at night when photosynthesis is not occurring but its a pretty insignificant amount. Are your fish going to be starved of oxygen because you have a ton of oxygen-producing aquatic plants? Nope. Also, keep in mind that the colder the water the greater its ability to harbor dissolved oxygen. And about warmth, these fish can overwinter under ice so they are no strangers to cold. I would certainly monitor the water temps and feed accordingly ( though.

  9. snguyentran says:

    Im planning on building an above ground koi pond about three to 4.5 feet deep in my screen house. I live in FL and already have established lotus and lily plants. How well will they do if I pot them? The article suggested the lotus for larger ponds; will mine be big enough?

    • Koi-Care staff says:

      Just don’t use commercial soil to do so -it floats. You want to get a soil that is a decent mixture of clay and sand (kind of heavier). You may not want to go all the way to the bottom in your situation. I wouldn’t put more than 20 inches of water over the top of the soil.

  10. Kathy Bamber says:

    Just starting a Koi pond and found this site to be so helpful.

  11. Cody says:

    So I have a 800 gallon koi pond and about 48 inches to its deepest point. With about 12 inches at its most shallow point, this is technically my hand made ledge. It has a hollowed out turtles log the koi use some times. It has great shade from my trees and a large purple azalea. I have a large water lily but was looking to get some oxygenating plants as well that are submersible. I saw the three that had been listed the hornwart was my first option but i was curious on “rotala” plants? Would this be a suitable submersible plant? And i was wondering where I could find some type of bamboo plant as well.

    I’m constantly manipulating the pond every year to make it better. I wanted to ask about adding in a bottom drain. I know I have the room and can make a slight slant as well so there’s some form of runoff to help get waste into the filter I was curious how cost effective the pump is and if it’s even worth putting one in.

    Finally my last question, I have never had any issue the past 2 years with any critters attempting to get my fish, birds or any four legged animals. I have four outdoor cats that love my pond and in a sense protect it. My question is i was thinking of putting up my netting agian this year. I had stretched it between my trees and about 8 feet up above the pond. I pulled it down because sadly there were a few incidences involving birds becoming snared and dieing. It was not my intentions to kill any animals but I also had an incident where my cat was tangled up with netting when I would lay it over the pond and I could not risk having my cat fall in and drown. Any way I can work around keeping leaves out of the pond with out negatively effecting the wild life around my house as well as protecting my own pets.

    Thanks so much for your feedback

    • Koi-Care staff says:

      Hi, sorry -you’re question somehow slipped past me and am just now seeing it. So to answer your question about rotala , the rotala rotundifolia is a great submerged plant and will even break the surface.
      As far as pumps are concerned the cost to run them will depend on the RPM’s, if you are running them 24/7, how big the pump is, the wattage, your kilowatt price per hour, etc. roughly $50 to 80 per month but again there are quite a few variables involved. If you already have a pump then it (bottom drain line) should simply hook into your pre-existing pump. They typically run from the bottom drain to a settling chamber then on to your pump. I am in the process of adding more to my store but I began by carrying Performance Pro pumps -they are American made and have a solid reputation.
      Now on to keeping birds and cats out of your pond. Thats a tough situation: one thing you could do is put an angled barrier of netting that originates near the water-land interface and angles in towards the center of the pond. Maybe something like a 45 degree angle and I believe that will keep the wading birds far enough away that they cannot strike at fish and the cats won’t get caught up in it. Sounds like your shelf is too deep for wading birds to land on anyway so I think the angled netting could work. Maybe make the fence something like 2-3 feet high? Though as i write this you could probably make the fence net vertical too.
      Hope this helps.

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