Koi and Pond Plants
There are 2 types of aquatic gardens, a koi garden and a water garden that is just for pond plants. If you plan to have koi in your pond, count on not having any plants. Commonly known as "water hogs", Koi are curious creatures and will eat the roots right off of floating water hyacinth and water lettuce. They will also chew the stems off of water lily right down to a nub. Although young yearlings may not harm your plants, mature koi will devastate your garden investment.
Can I have both koi and pond plants?
It is possible to have both koi and pond plants in the same garden, but it takes some planning and design. This is what the nursery at Seaside Gardens have done, see video. On one end of the pond they have their koi. The other side of their pond has a wall made of large river rock under the water making a barrier to keep the koi away from the plants. Plants can also be grown on a floating island or on shelves at the edge of the pond. I do not recommend netting to protect the plants as the fish may become tangled in the netting.
Another way to keep koi and pond plants in the same pool...
Water Hyacinth and Water Lettuce will not hurt your koi. These plants are actually used as cattle feed in some parts of South America. I have also known some gardeners that eat water hyacinth and water lettuce. I do not recommend it, because the plants are bitter. If you want to have plants in your pond with koi, I recommend that you grow your water hyacinth and water lettuce in a Rubbermade tub. They grow quickly enough that you can replace the plants the fish will nibble on.
What do I do with the old pond plants?
The old plants are a good additive to the mulch pile and are full of absorbed nutrients from the fish excrement, also known as fish emulsion - a water hyacinth and water lettuce are natural "fish" fertilizers which is very expensive to buy!
What kinds of fish will not harm my pond plants?
Yes! The common feeder gold fish will not harm pond plants. They come in a variety of colors and grow to about 5 inches long. They will also live for about 8 years. I rarely feed my goldfish and they do just fine. With water hyacinth in the garden, your gold fish will even have babies by laying their eggs in the thick water hyacinth roots. Other fish that do well in the pond are catfish and bluegill.