Do koi fish eat other fish?

In this brief article we will answer the question “do koi fish eat other fish?”. We will also discuss how to stop koi fish from eating other fishes.

Do koi fish eat other fish?

Yes, Koi will consume fish that are small that they can fit entirely inside their mouth. In most cases, they will consume fish, even if it is their own. Because they are only hostile toward a subset of other fish species, koi fish cannot be categorized as an aggressive fish in their entirety.  

Some fish will be attacked by koi fish, and the bite that they deliver can be fatal to the fish. Even though koi are generally peaceful, they are omnivores and may eat other fish if they get the chance.

Koi fish are frequently used in a variety of ornamental settings, including outdoor water gardens and ponds. They were bred specifically in Japan for the purpose of enhancing their vivid coloring.

At one time, these fish were only found in the colors red, black, blue and white however, today, they can be seen in a variety of color combinations including all of the colors. It wasn’t until the 1900s that people in the United Kingdom, Europe, and the U.s. began breeding koi.

How to stop Koi from consuming other fish ?

Keeping smaller fish in the same tank as koi can be challenging. Keeping koi and smaller fish in the same pond can be done successfully by some pond keepers, but if your koi are expressing interest in the other fish, there are several precautions you can take to keep them safe.

First and foremost, you need to check that the size of your pond is sufficient to comfortably house all of your fish once they have reached their full adult size. Keep your pond tidy and well-maintained, and provide your koi with an adequate amount of high-quality food to eat so that they won’t go hungry and won’t feel the need to hunt other fish for food. 

This will reduce the likelihood that they will attack other fish. You should also make sure that your pond has a number of different hiding places for the fish that are smaller. 

This may involve the addition of a substantial number of plants (which, in and of themselves, do a great deal to improve the quality of the water),fish shelters, rocks, tunnels and shallower places along the edge of the pond that are inaccessible to koi but provide a safe haven for smaller fish in the event of an emergency.

Because these areas will warm up more quickly than the rest of the pond, it is important to stock them with plenty of plants that can float and those that can emerge from the water, such as native water lilies. This will help to keep the water cool.

To what size do Koi grow?

The origin of a koi fish can have a significant impact on its size. Carp, of which koi are a subspecies, are typically very large fish and koi are no exception. Domestic koi, which range in length from 12 to 15 inches when fully grown, are the smallest species of koi. 

The average length of a Japanese koi is 22–26 inches, while the average length of a jumbo koi is 34–36 inches. The larger the fish, the more water it is necessary for them to consume. 

Your pond should be able to provide approximately 300 water gallons per fish for domestic koi up to 14 inches in length; larger koi require approximately 500 water gallons per fish; jumbo koi require up to 900 water gallons per fish.

Are adult Koi going to eat baby Koi?

The straightforward response to the question about whether or not koi consume their own young is “yes,” as it is well-documented that these fish do, in fact, consume their own offspring. Having said that, it is not always intentional on their part.

 Koi are omnivores, meaning they consume both animal and plant matter in their diets. Some of the foods they consume include algae, bugs, and flies. As a result, adult koi may eat their own young if they are still eggs or koi fry and don’t realize they are their own.

Eating their own young could be a sign of desperation for koi, who have relatively small mouths despite their large body sizes. Koi are known to eat their own young. They won’t be able to consume the food if it is of a portion size that is too large for them. If this were the case, then they could use their own eggs as a viable alternative.


In this brief article we have answered the question “do koi fish eat other fish?”. We have also discussed how to stop koi fish from eating other fishes.


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