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Pond Mates of Koi: A List of 9 Most Suitable Fish

Pond Mates of Koi

Pond Mates of Koi

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As a pond enthusiast, you must keep some fish as pond mates for koi fish. It helps to keep koi fish healthy & happy. You can keep other koi fish as pond mates too. It works well too. However, it can be expensive for the pond owners to maintain somehow. 

Here we will discuss a list of the 9 most suitable fish for koi fish. These fish are comparatively cheap & easy to maintain. Some of these fish will help to clean ponds too. You need to add them to your backyard koi pond. So without wasting time let’s dive deep into the topic. 

9 Most Suitable Pond Mates of Koi Fish 

Pond Mates of Koi Fish

1. Goldfish 

Comet Goldfish

Goldfish is a fabulous pond mate of koi. They can be kept in the same pond with koi fish easily. Pond enthusiasts keep goldfish and koi fish together because they both have almost the same characteristics and needs. 

Goldfish and koi fish are both peaceful cold water fish and they both have similar feeding habits. Not only that but goldfish don’t require high-level care like koi. You can easily keep these two fish together in your small pond at home (not recommended for fully adult koi in a small pond with goldfish, however you can start though) 

One factor you must consider is that If your goldfish is too small for a koi fish, koi fish can eat the goldfish. So you have to be careful when keeping goldfish and koi together. 

For example, you can keep comet goldfish with koi fish because comet goldfish are larger. These goldfish are strong enough to live with koi fish. Moreover, fancy goldfish like ranchu, telescopic eye goldfish, black moor, etc are not suitable to keep with any type of koi. Besides this, jumbo koi are not recommended for a small pond with goldfish as a pond mate. 

Read More:- Secrets of Keeping Koi & Goldfish Together: Is It Even Worthy

2. Pleco Fish 

Pleco Fish

Pleco or janitor fish is a tropical fish that can be kept in the same pond with koi fish very well after goldfish. This fish is very hardy and suitable for keeping in ponds. Because of their peaceful behavior, pond enthusiasts like to keep them. A good habit of this fish is that it keeps the pond water clean by eating pond algae and Koi fish like to live in clean water. So it is a win-win situation for both fish species. 

The average length of pleco fish is 15 inches but adults can reach up to 24 inches in length. So you need an average-sized pond to keep both of these species.  Pleco fish and koi fish are omnivores. They eat all living insects, including shrimp. Their favorite food is pond algae. Pleco fish are docile as juveniles but can become aggressive as they age. So try to keep pond decoration as simple as you can. 

One caveat to keeping this fish in the pond is to ensure that the water in the pond is warm, then this fish will grow very well. Non-tropical countrymen can use pond heaters to ensure the health of both of these fish. 

Read More:- How to Get Crystal Clear Koi Pond Water Right Away

3. Grass Carp 

Grass Carp

Grass carp can be the third choice for pond enthusiasts as the tank mate of koi. They are very beneficial to pond fish as they control the growth of aquatic weeds. Since this fish eats grass, this fish is named grass carp. Despite having some similarities the biggest difference between these two fish is their coloring. Koi fish are mostly a colorful combination of red, yellow white & black but mostly grass carp are dark brown.

Koi and grass carp are closely related fishes but these two fishes have completely different characteristics. Koi fish are beautiful and decorative fish but carp are ordinary-looking fish. Koi fish belong to only one species but carps belong to different species.

Furthermore, these two fish are freshwater fish and these two fish can be kept together but ensure that the water is clean and the water temperature is moderate. 

4. Tilapia


Tilapia is a suitable tank mate for koi. They are omnivorous fish that survive by eating plants and small animals in ponds. The cost of caring for this fish is meager. Similarly koi fish are omnivorous, they eat small insects in ponds. Since these two are omnivores, they can be kept together. 

There are some differences between the water temperature of these two fish. The koi fish’s immune system can become impaired when the temperature goes above 50°F. Whereas tilapia fish can withstand temperatures up to 75°F.

Care must be taken to ensure that the pH of the water is correct, koi fish grow at the 7 pH scale and tilapia grow at the 9 pH level. However, you should not be confused by seeing such pH levels. You can average it out and maintain the right pH for your pond, both of these fish can adapt it well.  

Read More:- How to Grow Koi Fast up to 2-2.5 Feet: 5 Steps Guides

5. Redear Sunfish 

redear sunfish

Both sunfish and koi fish can live together in a pond because they have almost the same characteristics. They are both freshwater fish and both are peaceful community fish. However, sometimes the sunfish shows aggressive behavior.

Sunfish can be up to twenty inches long in size. But some smaller species of sunfish grow from 3 to 6 inches long. Koi fish range in size from 14 inches to twenty inches long. These two fish can be kept together very well due to their consistency in length and size. However, a large pond is required to fit both of these species well. 

These two fish have similar eating habits so it is helpful to keep the two fish together. One thing to be careful about is that the sunfish should not be smaller than the koi otherwise the koi may attack the sunfish.

6. Golden Orfe

Golden Orfe

When a golden Orfe and a golden koi fish swim together you can’t recognize which is the golden Orfe and which is the golden koi, as the two look almost identical. There is very little difference between these two fish. Golden Orfe fish bodies are similar to koi fish.

If you want to keep them in the same pond with koi, you need to make sure the water is well filtered. Though bottom feeders, golden Orfe fish help to keep the water clean of the pond. So koi can be kept with this fish easily.

Care must be taken to ensure that the pond has an adequate supply of oxygen. You can keep two to three Orfe together with koi fish.

7. Barbel

Barbel Fish

Koi fish can be compatible with barbel fish. Barbel is a European fish. Barbels can be up to four feet long. The life span of the barbel is up to twenty years. Since they are similar in size to koi fish, they can be good pond mates for koi fish. The temperature requirements and feeding habits of the two fishes are almost similar. This fish requires very little care compared to koi fish.

They are a bottom feeder like janitor fish & golden orfe. Barbel can eat excess uneaten food from koi fish or other animals in the pond. It helps to clean a pond very efficiently.  

Larger barbel and adult koi should be kept together to avoid fighting. Water flow in the pond should be good for these two fish. Good water flow helps both of these fish to be healthy.

8. Iridescent Shark 

Iridescent Shark

Iridescent shark fish can grow up to 3 feet in size in backyard ponds. They prefer the temperature of the water should be between 72°F. to 75°F which is good for koi fish too.

Iridescent sharks and koi fish have almost the same diet as they are both omnivores so both can be fed the same healthy diet. Iridescent sharks need a variety of food. As they eat too much so you need to stock a certain amount of food for both koi & iridescent sharks.  

Like koi fish, this fish is quite large, so keeping these two fish together requires a pond with a large amount of water. This fish is very healthy and happy when it is in a group in rivers. But when this fish is kept alone, this fish becomes calm and looks very apathetic. However, in backyard ponds, it is not possible to keep them in a group. With koi fish, they can live well.   

9. Barbs 

Five Banded barb

Barbs are manly aquarium fish but can stay in the backyard pond too as a pond mate of koi fish. However, each and every barb species aren’t suitable for koi ponds due to their small size. Some barbs like tinfoil barbs grow up to 14 inches long and can live in a koi pond easily.  

Barbs can live up to 6 years in a pond if they are fed good quality food and the water quality is good. They are omnivores so they can easily stay on the same diet as koi fish. Barbs are colorful fish like are are are fish and available in a variety of colors. These two fish are beautiful in the pond.

Read More:- 10 varieties of Koi Fish: Origin, Description & Pictures

Final Thoughts 

Koi is a very sophisticated fish. So you need to choose their pond mates wisely. If you keep butterfly koi then you must not keep any kind of fin nippers. Otherwise, the beautiful fins of koi will be lost. 

If you keep a jumbo koi in a small pond then don’t need to keep other fish named as pond mate. Otherwise, it will create a mess. However, we have recommended the top 9 fish as pond mates of koi. From this list, you can choose any one or two of them.   

According to our best pick, big goldfish & janitor fish works well as pond mate of koi. However, if you keep them together a strong filtration system is mandatory. Don’t mix any juvenile fish with adult fish anyhow. So it should be kept in mind. 

Best of luck & happy fish keeping.    

Read More:- How to Get Crystal Clear Koi Pond Water Right Away

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