What koi eat
Koi are omnivores. In natural waters their carp relatives eat plants, algae, insects, worms, crustaceans, and whatever else they can find along the bottom and in the water column. In a pond, most of that diet is replaced by a prepared koi food, with occasional fresh or frozen extras.
Because koi are active and long-lived, what you feed them affects growth, color, and water quality. Overfeeding is a more common problem than underfeeding, since uneaten food and extra waste raise ammonia and feed algae.
Types of koi food
Most keepers rely on a floating pellet made for koi. Typical categories include:
- Staple or all-season foods: Everyday diets, often built around wheat germ because it is relatively easy to digest.
- Growth foods: Higher in protein, intended for young or growing koi in warm water.
- Color-enhancing foods: Often contain ingredients such as spirulina or other pigments that support red and orange tones.
- Health or immune-support foods: Fortified with vitamins and minerals.
Floating pellets let you watch your fish eat and see how much they finish. Pellet sizes also vary, so choose a size your fish can eat comfortably. Check the date on the bag and store food in a cool, dry place, since vitamins degrade over time. Many manufacturers suggest using a bag within a few months of opening.
How much and how often to feed
A common guideline is to feed only what the koi can eat in a few minutes, then remove the rest. Sources vary from roughly two to five minutes per feeding, so treat this as an approximation and adjust to your pond. If food is left floating after that, you are probably feeding too much.
Frequency depends on temperature, fish size, and the food type. In warm water, many keepers feed small portions once to several times a day. Smaller meals spread out can be easier on the pond’s filter than a single large meal. Young, growing koi usually eat more often than mature fish.
Feeding by water temperature
Koi are cold-blooded, so their metabolism follows the pond. As the water cools, digestion slows.
- Warm water: Regular feeding of a quality food, with growth or color foods used if you choose.
- Cooler water: Many keepers switch to a wheat germ-based cold-water food and feed less often.
- Cold water: Feeding is usually reduced or stopped. A frequently cited threshold is around 50 degrees Fahrenheit (10 degrees Celsius), although guides place the cutoff anywhere from the mid-40s to about 50 degrees F.
Koi may still approach and beg for food when it is cold, but undigested food can cause problems for the fish and the water. We explain this in more detail in our guide to koi fish winter care. A pond thermometer is more reliable than air temperature.
Treats and natural foods
Many koi enjoy variety. Items commonly offered in small amounts include:
- Shelled peas, lettuce, or other leafy greens
- Watermelon or orange pieces
- Earthworms, freeze-dried or frozen shrimp, and krill
- Silkworm pupae, which some keepers use as a protein supplement
Treats should be occasional and small, and anything uneaten should be removed. Avoid anything seasoned, salted, fried, or sugary. Frozen foods should be thawed first.
Can koi eat meat?
Koi can eat animal protein, and in nature they eat insects, worms, and small invertebrates. Safe options in a pond are generally small portions of worms, shrimp, or krill, or the protein built into a koi pellet. Cooked or raw meat from land animals is not a typical koi food and is easy to overdo, since fats can foul the water. If you want to offer protein, stick to aquatic-appropriate foods.
Can koi eat rice?
Koi will often take plain cooked rice and other starchy foods, but it is not nutritionally complete and offers little compared with a proper koi pellet. If you try it at all, keep it to a tiny, occasional amount of plain rice with no oil, salt, or seasoning, and do not use it as a replacement for koi food. Many keepers simply skip it.
What is the best food for koi and goldfish?
Koi and goldfish are related, and both can eat many similar ingredients, but their foods are not always interchangeable. Koi-specific foods are designed for larger fish that eat in volume and for pond conditions. Goldfish foods are tuned for goldfish, which come in many body shapes. Occasionally sharing is not likely to cause harm, but for the long term choose a food made for the species you actually keep, from a reputable brand, in a pellet size your fish can handle. If you keep both in one pond, a quality koi or pond food is a common solution.
Signs you are overfeeding
- Food still floating after several minutes
- Cloudy or green water, or persistent algae
- Rising ammonia or nitrite readings
- Stringy waste trailing from the fish
If you see these, cut portions and review your filtration. For broader pond care, our guide to taking care of koi fish covers water quality and routine upkeep.
Can people eat koi?
Koi are technically a form of carp, so they are edible in principle, but eating ornamental koi is not generally recommended. They may have been exposed to medications or pond chemicals that are not meant for food fish, and carp have many small bones. Treat koi as pets, not food.