How to Keep Koi from Eating Your Pond Plants

Pond owners love their colorful koi, and they equally love their pond plants. Yet many struggle to keep their koi from making a feast of their favorite waterlilies. What’s a water gardener to do? Never fear, it really is possible for koi and aquatic plants to live in harmony in the same pond.


Large White Koi in Pond



The key to the plant-eating koi dilemma is to make sure you have the correct koi-stocking density for your water garden. Put too many koi in a pond and they’ll compete for everything – especially food. Your ravaged waterlilies are simply evidence of hungry koi!

A good general rule of thumb for koi stocking is to have no more than one inch of fish per 10 gallons of water. So you can have 150 inches of fish in 1,500 gallons of water, which is about five koi. Remember, when buying small fish, they’re going to get bigger. So choose fish based on how large they’re going to grow. If you don’t provide koi with enough room, you risk plant health, water clarity, and the fish will suffer from stressful living conditions.

Understanding and Feeding Koi

Keep in mind that koi are inquisitive fish and explore their surroundings with their mouths. If you catch them rooting around the base of your waterlilies, simply use larger rocks around the base of the plant so the fish can’t move them and destroy the planting.

If your koi are well fed, they won’t eat many plants. Although they love dining on your favorite waterlily, they prefer koi food even more. Given the choice between a pelleted food and green vegetation, they’ll opt for the taste and high-energy of a pelleted food. Feed your fish once or twice a day for five minutes at a time and they’ll be satisfied enough to steer clear of your plants.

When choosing fish food, the pellet size should be close to the size of the fish’s pupil (the black part of the eye). Toss in a few pellets for starters, and then throw in more food over the course of approximately 5-7 minutes. Excess food is caught in the skimmer and will decay, which isn’t ideal for the water quality of your pond. This is why it’s preferably to toss in a few food pellets at a time, as opposed to a large handful.

The truth is that aquatic plants and fish complement one another. Combining the two creates a healthier, cleaner pond that’s easier to maintain. Pond plants offer coverage from predators, reduce nitrates, and oxygenate the water during the day. And plants like water hyacinths remove toxins better than any chemical absorbent. Just remember not to overstock the pond and to feed your koi a quality fish food on a regular basis. You’ll find that koi and aquatic plants can live in peace and harmony, providing you with hours of water gardening enjoyment.