5 Aquatic Creatures That Would Live Harmoniously in the Koi Pond

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In contradiction to what you might think, koi can coexist in harmony with other fish. We’ve found that the majority of koi owners are often worried to add new species to their pond. Their primary concern is usually the wellbeing of the new fish and the koi, the chemical balance, pollution or the need to change the water’s temperatures and pH, which can be very dangerous for the entire ecosystem.

5 Aquatic Creatures That Would Live Harmoniously in the Koi Pond

There are several kinds of fish that will get along just fine with the koi and their established habitat. In fact, some of them will actually be quite helpful with the algae control and water quality maintenance. The best choice is typically fish that live on the other water levels in order to avoid the competition for food.


goldfish pond, koi pond, goldfish and koi, pond construction, pond fish The most common choice for many pond owners is to put goldfish in with their koi. They can live in harmony without a problem, yet the koi and goldfish can have a hybrid generation, and it’s not known to inherit their beautiful looks. Koi and goldfish share about the same water and weather condition needs. Keep in mind that they both feed on the surface and you will have to give extra food.


plecos, freshwater aquarium, algae eaters, algae eating fish, aquarium steup, aquarium maintenance, janitor fish Another common choice is adopting a janitor fish for the pond. An algae-eating fish like the common plecostomus or the golden nugget plecos will usually not disturb your koi. They are bottom-dwelling catfish and will stay busy eating off the algae and will rarely go to the surface. The plecos are a hardy fish and can survive in the same conditions as the koi. Best practice is to introduce a couple plecos only, depending on your pond’s size and current koi fish count. They also have beautiful colors and distinctive patterns.


rainbowfish. Melanotaenia, koi pond, fish pond, pond fish, pond construction, pond fish selection
A Melanotaenia, Image source: Wikipedia

The rainbow fish also does well in the same pond as the koi. They usually live in harmony with community type fishes. Rainbow fish are omnivorous and their diet includes small crustaceans, insect larvae, and algae. However, they will not neglect the tasty fish food floating around. Hence, just like the plecos, they will lend a helping fin with the maintenance of your pond. They aren’t aggressive, but according to most fish owners, you should have only one male rainbow fish in your water feature.


japanese trapdoor snail, koi fish, fis pond, japanese koi, pond construction, aquatic creatures, pond fish choice

The Japanese trapdoor snail is an aquatic creature meant to live in the koi pond. They are nothing like the common snails you see around. This type of snail has no interest in the koi and the fish have no interest in them. They also take care of the water’s quality by tirelessly eating of the algae. The Japanese trapdoor snail is a unique “mystery” snail that will even give you a tip when you need to check on the water of your pond or aquarium.


It is known that some zoos and aquariums open to the public have tilapia in the same pond as koi. The tilapia is a non-aggressive freshwater cichlid that will feed on the algae and other plant-based food, and fish food, so you will have to sprinkle some extra of that in. 


Before you introduce another pond fish or aquatic creature, it’s best to consult with your local pond specialist. As a premium fish dealer and koi breeder in California, here at Mr. Fish, we strongly advise you to proceed with caution and only buy fish from a certified fish store.