Can Koi Eat Cat Food? Let’s Find Out

Cat and koi fish

Koi are stunning Japanese fish that boast gorgeous colors and make great pets. They are generally easy to care for and will eat almost anything that we do. Since it can become a little costly to purchase specific koi food, you may wonder from time to time: Can koi eat cat food? We’ve wondered the same thing and have done some digging.

Koi can eat cat and dog food; however, it is not advisable to make it their staple diet. Koi struggle to digest animal fats and dairy products since these are not found in their natural habitat. Most pet foods contain these, so your koi will become malnourished in the long run.

We all know that koi enjoy eating fish food, but a lot of people aren’t aware that they also enjoy eating certain human foods. Since koi can and do eat a wide variety of foods, we think it’s fair to ask if they can eat cat food. Let’s find out as we uncover what koi should eat, what is in cat food, and if the two align.

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Can Koi Eat Cat Food?

Koi can eat various foods, but can they eat cat food? Let’s look at the healthiest and most natural options for koi and what is inside cat food. Once we can make a comparison, we will have our answer.

You may be wondering what other foods koi fish can eat, such as rice or bread; if so, you can read my blog posts here: can koi fish eat rice? and can koi fish eat bread?

What Do Koi Typically Eat?

Giant freshwater prawn or giant river shrimp in tank
Giant river shrimp in a tank

Koi fish eat slightly differently, depending on their age and size. Baby koi enjoy fish food in the form of flakes. Medium or average-sized koi enjoy fish pellets, and large koi prefer fish food bars. What all of these fish foods have in common are their ingredients.

You can also make your own homemade Koi food for adult Koi fish and Baby Koi fish using healthy ingredients such as shrimp, sweet potatoes, peas, and more. You can learn how to cook homemade Koi food pellets and pastes by reading my blog post: A complete guide to making homemade Koi food.

Koi fish have difficulty digesting carbohydrates, dairy products, and animal fats. These types of food are not naturally in their diet since they are not typically found in ponds and lakes where koi are found. So, if fish food has no carbohydrates, animal fats, or dairy products, what does it contain?

Fish food typically contains essential minerals and vitamins, very little fat, and a large amount of protein. Koi fish also benefit from eating clams, shrimp, larvae, tadpoles, and worms. This is what a koi would typically eat if fending for themselves in their natural habitat.

If you want to learn more about Koi’s diet in the wild, you can read my blog post: Worms: should Koi eat them?

If you consider feeding your koi shrimp, worms, and the like, please avoid providing them with wild specimens you have caught yourself. They could be contaminated with diseases that will then be passed to your fish.

What Is In Cat Food?

Fat Cat Eating Heaping Bowl of Food
Cat Eating Heaping Bowl of Food

Cat food comes in two varieties. Dry kibble and wet food. Since cats are carnivores (they rely on meat for sustenance), their bodies cannot process vegetables. The kibble that we feed cats is, therefore, mostly meat.  

The meat used in cat kibble is cooked at very high temperatures. It undergoes a few processes before being molded into the shapes we know. Cat kibble contains many carbohydrates, which helps the kibble keep its form.  

Wet-type cat food is available in cans or pouches. It is a meat form, like fish, chicken, or beef, housed in jelly.

Is Cat Food Healthy For Koi Fish?

Based on what we have learned about koi and cat food, it would seem that cat food is not the best option for koi to eat.

We know that koi have difficulty digesting carbohydrates, animal fats, and dairy products. 

We have learned about cat food that kibble contains high amounts of carbohydrates. Wet cat food has meat from land animals, like chickens and cows. 

Perhaps the healthiest cat food option for koi is the wet fish option. The only issue with it is the jelly, usually made from turkey. Since turkey is a land animal, koi will likely struggle to digest it.

Although cat food is not particularly healthy for koi to eat as a staple part of their diet, it is perfectly acceptable for them to eat it as a snack from time to time. Koi do find cat food quite tasty.

Can Koi Eat Cat Food, And Should They?

When considering if koi can eat cat food, the simple answer is yes. Since koi can eat several human foods, we imagine they can eat dog and cat food too. Some koi owners have been known to give cat food to underweight koi, as it helps bulk them up somewhat.

To learn more, you can read my blog post: Can Koi eat Dog food?

The adage: “There are some things you should not do, even if you can do them.” It comes to mind with whether or not koi should eat cat food. Yes, they can eat it, but the hard truth is that it is not very good for them.

Koi owner, Sean Hefer, explained that koi can sometimes be suffering internally but look alright on the outside for quite some time. He says it may seem like your koi are enjoying the cat food you provide and thriving on it, but their health may be suffering.  

Sean told us that koi could eat fruit, vegetables, and other foods low in carbohydrates. Since cat food is high in carbohydrates and animal fats, it should not be fed to koi fish very often.

What Snacks Can I Give My Koi?

Koi are loyal companions, and you may want to treat them occasionally. Although you need to provide them with food created especially for koi, it is possible to give them tasty snacks to brighten up their lives as much as they brighten up yours. Let’s look at a few delicious and healthy snacks you can provide your koi.

Dog Food

Although dog kibble is not recommended as a staple food for koi, it can provide a tasty snack between meals. Try to stick to natural and pure dog food to ensure your koi stay healthy after their snack.

Shrimp, Crayfish, And Worms

Did you know that koi are omnivores? That means that they should eat a mixture of meat and plant matter. Your koi will love a snack of shrimp, crayfish, or worms. It is better to provide these from a distributor than the ones you have caught yourself. Animals caught in the wild could carry parasites or sickness to your koi at home.


Koi fish eating a watermelon
Koi fish eating a watermelon

Yes, fruit! Koi love fruit, making an excellent snack for them between meals. Fruit is healthy for koi and helps keep their immune systems in check. Great fruits to consider include:

  • Grapes
  • Watermelon
  • Oranges

You may decide to cut the fruit into smaller pieces for your smaller koi; however, larger koi should be able to eat large pieces.


Tasty Broccoli

Your koi will love to work together to tear up lettuce and broccoli and get a health boost from the benefits of these green vegetables. Koi usually enjoy vegetables, and we say, with all the health benefits, why not?

Cat Food

We know we have told you why cat food is unsuitable for koi. It does not make good food part of their staple diet; however, it is excellent as a snack between healthier meals. What your koi cannot digest will pass through, but they will enjoy the experience of eating cat food as a snack from time to time.

Also, see: Can Koi fish eat bread?


Koi can eat cat food, but it should not be used to substitute for real fish food. Since koi cannot digest carbohydrates, animal fats, or dairy products, cat food is not a good option for them as a staple food. Cat food, dog food, fruit, vegetables, and some meat can be used as tasty snacks for koi between their regular healthy meals.


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