The simple answer is don't put plants in a koi pond.
The fish will stir up the roots and make the water dirty.
The fish can damage themselves on the plants.
The larger fish will eat them.
Make sure you have a good filtration system and you don't need plants.
If you want plants to enhance the pond then have a small pond alongside and use it as a veggie filter with water passing through the small pond to the main pond.
Posted on Oct 31, 2007, 9:03 AM from IP address 86.152.27.241