Plants in Koi Ponds

We have had several of our clients ask us if it is okay to put plants in koi ponds. Simple answer? Yes!

But aren’t plants bad for fish?

Not one published scientific study has shown any plants attacking fish. Yes, they may be carrying different bacteria or parasites, but you can avoid this by simple quarantine.


But my fish eat my plants!

Being omnivorous, it’s not surprising that koi like to nibble on your plants. Free-floating plants, such as hyacinths and water lettuce are common munchables. Rooted plants such as lilies and lotuses are less often eaten, but some fish can’t stay away!

To prevent your fish from eating your plants, make sure you are feeding them correctly. Koi should be eating koi food and being fed more during warmer water temperatures. Protect your plants by placing them in floating rings with netting to prevent fish from accessing them. Or separate an area of your pond where the water can flow, but the fish can’t access. This is typically referred to as a “bog.”


But they can bring diseases!

If your plants are coming from a system that does not contain fish, come in contact with fish or water containing fish, they are safe to add to your pond. You will need to ask your plant supplier these specific questions to know for sure.

If your plants have been in any sort of contact with fish, quarantine them like you would your fish. By removing fish from their environment, you will break the life cycle of all the bacteria and parasites. Depending on your water temperature, you are looking at 2-3 weeks to decontaminate. Don’t forget to fertilize your plants in quarantine until they can soak up your nitrate-rich water in your main pond.


I don’t need to do water changes because the plants will soak up all the nitrate!

In order to make a significant impact on your nitrate levels, your pond needs to be 1/4-1/3 plants. Adding 2-3 lilies and ignoring your water changes will not suffice. Adding an aquaponic setup can do a lot for your nitrate levels and grow some tasty vegetables!

Simply put: you can put plants in your koi pond. For more information on aquatic plants and adding them to other systems, click here.

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