What Do Koi Fish Eat? Koi Food & Seasonal Feeding Guide
Apr 19th 2024
What Do Koi Fish Eat? The Quick Answer
Koi are omnivores. In a pond they graze on algae, plants, insects and other small organisms, but a quality koi pellet sized to your fish should be their staple diet. How much and what you feed changes with water temperature: koi eat the most in warm months, need easier-to-digest food in spring and fall, and should not be fed once the water turns cold in winter. Occasional treats such as lettuce, peas or watermelon can be offered in small, bite-size pieces.
Not only are koi fish beautiful to look at, they also bring a smile to your face when they come to you for food, especially if you are the one always feeding them. They remember their feeder! Feeding koi can be a delightful activity performed alone or with your loved ones, as you feed the koi together. If you treat them well, koi will sometimes even literally eat out of the palm of your hand. This guide covers what koi eat, how to choose the right koi food, and how feeding should change through the seasons.
What Koi Eat Naturally in a Pond
Koi are not fussy eaters. In an established pond they forage on algae, aquatic plants, insects, larvae and other small organisms, which is why they can get by for a while if a feeding is missed. Natural forage is not a complete diet for most backyard koi, so a quality koi food should supply the bulk of their nutrition, with any supplements used as directed on the label.
Choosing Koi Food by Fish Size
Choose koi food by the size of your fish. Smaller koi do best with flakes or small pellets they can swallow easily, while larger koi prefer medium or large pellets. If your pond holds a mix of sizes, offering two pellet sizes helps every fish get its share. Browse our koi and pond fish food to compare pellet sizes and formulas.
How Koi Diets Change With the Seasons
Koi are cold-blooded, so their metabolism rises and falls with water temperature. Matching their food to the season helps them digest it fully and keeps uneaten food from fouling the water. A pond thermometer is the easiest way to know when to make each change.
Spring and Fall: Easy-to-Digest Foods
In early spring and late fall, when the water is cool, choose an easy-to-digest food such as a wheat germ or cold-water formula and feed smaller amounts. Switch to a cold-water food once the water reaches 55°F or lower.
Summer: Higher-Protein Foods
In summer, when koi are most active, growing quickly and spawning, they can use a higher-protein koi food. Feed small portions they finish quickly, because warm water holds less oxygen and leftover food breaks down fast.
Winter: When to Stop Feeding Koi
As the water keeps cooling, koi eat less and less. Stop feeding once the water stays at or below 50°F and wait until it warms back up in spring before starting again with a cold-water food. Koi rest near the bottom through winter and can go the whole season without food. See our winter feeding guide for Japanese koi for more detail.
| Season | Water | What to feed | How much |
|---|---|---|---|
| Spring | Cool, warming | Wheat germ or cold-water food | Small amounts, increase as it warms |
| Summer | Warm | Quality staple or higher-protein pellet | Small portions up to four times a day |
| Fall | Cooling | Wheat germ or cold-water food (55°F or lower) | Small amounts, taper off |
| Winter | Cold | Nothing once at or below 50°F | Do not feed until spring |
Safe Treats Koi Can Eat
Koi also enjoy occasional treats, which can make feeding time even more interactive. Lettuce, peas, watermelon and shrimp are popular choices when cut into small, bite-size pieces. Treats should stay a small part of the diet, with a quality koi food as the staple, and any uneaten pieces should be netted out so they do not break down in the pond.
When Not to Feed Your Koi
Skip or reduce feeding whenever your pond's oxygen may be low. Fish need more oxygen while they digest, and hot, still, overcast or stormy weather can lower the amount of oxygen dissolved in pond water. The same applies if your pump, aerator or waterfall stops running: hold off on feeding until circulation is restored. If your koi are gasping at the surface, contact our pond service team.
How Often to Feed Koi
In the warm months, feed koi small amounts up to four times a day, offering only as much as they can eat in three to five minutes. Smaller, more frequent feedings are easier on your filtration than one large meal. Regular feeding times also help koi learn to recognize you, and many will come to the surface to greet you when it is time to eat.
Signs You Are Overfeeding
Food left floating after five minutes, cloudy or green water, and rising ammonia readings on a test kit can all point to overfeeding. Cut portions back, net out leftovers, and test your water. Our koi pond water parameters guide explains what to test and the ranges to aim for.
Koi Feeding FAQs
What is the best food for koi fish?
A quality koi pellet sized to your fish is the best everyday food. Choose a wheat germ or cold-water formula in cool spring and fall water and a higher-protein formula in summer.
How often should you feed koi?
In warm weather, feed small amounts up to four times a day, only as much as your koi finish in three to five minutes. Feed less often as the water cools.
Do koi need to be fed in winter?
No. Koi slow down as the water cools and should not be fed once it stays at or below 50°F. Resume in spring with a cold-water food.
Can koi survive without being fed?
For a while, yes. Koi forage on algae, plants and insects in an established pond, so a missed feeding is usually fine. Regular feeding with a quality koi food is still needed for healthy growth.
Can koi eat human food?
Some, in moderation. Lettuce, peas, watermelon and shrimp cut into small pieces make good occasional treats. Keep treats to a small share of the diet.
Get Help Choosing the Right Koi Food
Not sure which food fits your pond? Visit one of our retail stores or contact our team for help choosing the right koi food for your fish, your pond and the season. You can also shop koi food online.
