Hornwort in Koi Ponds
Hornwort may not be the best plant choice for a koi pond. While it tolerates many water conditions and helps remove nutrients, koi love to eat hornwort.
Why It Can Be Problematic
Because hornwort is fragile, koi may consume it before it can provide lasting benefits to the pond ecosystem. For this reason, other pond plant options are generally preferred.
If you want live plants in a koi pond, consider hardier species that can withstand nibbling and rooting behavior.