Can Angelfish Live With Koi?

Angel fish and his eggs baby

Angelfish and koi are beautiful fish, and many pond and aquarium enthusiasts keep each species. But suppose you want to increase the biodiversity of your pond or aquarium. You think these two fish would be great together because of their beauty and temperament. In that case, you may ask: Can angelfish live with koi?

Angelfish and koi can live together, but it is not recommended to do so. The water temperature, water quality, and diet requirements are different, making it difficult to manage both simultaneously. In most cases, one species will suffer to accommodate the requirements of the other.

Understanding the nature of each fish and its requirements will help you decide whether you should keep angelfish and koi together. Below we discuss the nature of each fish species and its needs to help you make an informed decision.

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Koi fish

Angelfish And Koi Characteristics

My Beautiful Angel Fish Up Close and Personal

Angelfish are tropical freshwater fish from South America. Their peaceful nature, graceful swimming style, and beautiful colors and shape make them a sought-after fish for aquarium enthusiasts. 

Angelfish are peaceful and are usually happy to live with other non-aggressive fish. While they can be kept individually, they are happiest when put in groups in an aquarium. They grow to about 6 inches and prefer to be in a tank with the same size or smaller fish.

Angelfish may become territorial if their space is invaded or when they are breeding.

Koi are also beautiful freshwater fish, but they come from Japan. Their fin and body shape, as well as their beautiful coloring and patterns, are what make them iconic and sought-after fish. While they are also peaceful fish, they can grow up to two feet long, much larger than an angelfish.

Koi also prefer to be in groups. They are social and friendly fish. Still, they need a large aquarium or pond because they are large fish. They can become agitated and aggressive during feeding. 

Koi fish

Difficulties Of Keeping Angelfish And Koi Together

A portrait of a zebra Angelfish in tank fish with blurred background Pterophyllum scalare

While angelfish and koi are peaceful and will happily live together based on their temperament, their physical needs are different, and you will encounter several potential issues if they live together.

Water Temperature Requirements For Angelfish And Koi

Angelfish require a water temperature between 75-82 degrees Fahrenheit. Koi, on the other hand, prefer colder water between 50-75 degrees Fahrenheit. 

Because there is only a small overlap in temperature, keeping both fish in the same tank or pond will mean one species will live in an undesirable water temperature and put it under stress, or both fish will live on the edge of their comfortable water temperature. Both species will become stressed and susceptible to illness.

Size Difference Between Koi And Angelfish

The size difference between grown angelfish and koi can be significant. Angelfish grow to about 6-7 inches long (including fins) and 8-12 inches high (including fins), and koi can grow up to 15 inches long, but some breeds can grow as long as 30 inches. 

Koi will need a larger space to swim, and because of this, the relatively small angelfish may be too small for the size pond needed for the koi. If smaller angelfish live with large koi, the koi will dominate the space and resources in the pond or aquarium. 

Also, angelfish are slower swimmers and may not get to the food as fast as the koi or may be pushed out of the way. 

All these factors may lead to angelfish or ill health distress due to competition for food and resources.

Water Quality Requirements Of Koi And Angelfish

The water quality of a pond or aquarium that holds koi can often deteriorate quickly. This is because koi produce a lot of waste, altering the water quality. A good filtration system will assist in keeping the water quality at the correct levels. Still, even in the best scenarios, this may not be good enough for angelfish.

Angelfish require clean water to keep healthy. If the water quality is already low from the koi being in the pond or aquarium and angelfish are introduced, this will further decrease the water quality. 

Should the water quality drop too low, it can cause stress and illness in both species and may even lead to death in extreme cases.

This table will give you information at a glance for what both species require:

Water RequirementAngelfishKoi
HabitatSlow-moving water and shaded habitat, no direct sunlightOpen water with some direct sunlight and plants/rocks to hide in or behind
Tank/Pond Size55-gallon tank per 4-5 fish1000 gallons per group of fish at a depth of at least three feet.
pH Level of WaterBetween 6.8-7.8Between 7.0-8.5
Water HardnessBetween 3-8 degrees dKH (54-145 ppm)Between 9-15 degrees dKH
Water TemperatureBetween 75-82 degrees FahrenheitBetween 50-70 degrees Fahrenheit

Maintaining a balanced and stable environment for both fish is important for their health and well-being.

Diet And Feeding Habits Of Koi And Angelfish

While both fish are freshwater species, their diet and feeding habits are very different. 

Angelfish are omnivorous. They are usually fed one or all of the following:

  • Pellets
  • Flake Fish Food for carnivores
  • Worms: bloodworms, white worms, mealworms
  • Small insects
  • Small crustaceans
  • Some frozen foods

Koi, conversely, are mostly herbivores who occasionally eat small insects or other protein sources. They are usually fed one or all of the following:

  • Flake Fish Food for herbivores
  • Koi Pellets
  • Peas, lettuce, cauliflower, broccoli
  • Watermelon, melon, grapes, strawberries (sliced to the size of their mouth)
  • Pasta, rice, and oatmeal (in very small amounts)
  • Earthworms, cooked and peeled shrimps

Feeding these two very different types of foods to each fish species in the same aquarium or pond could become tricky. This is especially difficult if the larger koi dominate feeding time and get to the angelfish food before the angelfish. Then not only are the angelfish not getting enough food, but the koi are also getting the wrong kind of food in addition to too much food.

The feeding frequency between the two species is also different. Because koi are larger and more active than angelfish, they require more food more often. Ideally, koi should be fed large portions several times a day. On the other hand, angelfish only need to be fed small portions about twice a day. 

The difference in types and amounts of food and frequency of feeding can make it difficult to keep both species living together without one or both becoming distressed because of food and feeding.

Should You Keep Angelfish And Koi Together?

A closeup of a freshwater angelfish, beautiful and popular aquarium pet, tropical fish from the amazon basin

While it is possible to keep the two species of fish in the same aquarium or pond, it is not advisable. The difference in size, feeding habits, and water requirements of both species will make it difficult to keep them living together and may actually be detrimental to one or both species.

Koi fish


Angelfish and koi can live together, but we don’t recommend you do so. As a fish enthusiast, maintaining each species’ water temperature, water quality, and diet will be difficult and require a lot of additional work. This may distract from the original reason to keep the fish – their amazing beauty. It may also be detrimental to the fish as one species may suffer to accommodate the other in the tank or pond.


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