Why Do Fish Swim In Circles? Have you ever witnessed a school of fish or even an individual fish swimming in a circular motion? Maybe you are wondering if it is normal or is it something you should be worried about.

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Well, though there is still no fixed explanation of why fishes do this, we listed some possible reasons why fishes swim in circles.

He Wants To Play

Fish are naturally playful creatures. They love to roam around and hide. When a fish swims in circles, it could be that it is just playing around or having an exercise. When a fish, especially a goldfish, lives in a fishbowl, it could be that he is imitating the round surface of his tank. It is normal, if this is the case, and you should not worry about your fish.

They Want To Stay Put

Fishes often swim as a group referred to like school. Sometimes, a school of fish moves in a certain place in a circular motion simply because they want to stay in that place. Maybe that area has food or some tourist spot or object they find as fun. Swimming in circles may indicate that the school of fishes wants to stay put in a certain area. In this case, you do not have to worry again.

They Want To Prevent Predators

Fishes are natural prey also. They could be attacked by predators like sharks and other bigger fishes. It would be better for these fishes to swim as a group so to lessen the chance of getting eaten by predators. When these schools sensed danger, swimming in circles can be a part of their survival techniques.

He Is Poisoned

If you noticed that your fish is or are swimming in circles constantly for a long time, it might indicate that something is wrong.  Try to check the water quality, pH, ammonia, and nitrite levels. If the motion is jerky, rapid, and panicky, the fish might be having an ammonia poisoning.

He Has A Parasite

If your fish is continually swimming in a circular motion, it could also be caused by a parasite. The fish may have gotten a whirling disease wherein a parasite has attached himself onto the equilibrium organ of the host. Also, observe if the fish would rub himself against something then swim away. It could be that an external parasite is living with him.

So there listed some probable reasons why fishes swim in circles. Do you know other reasons that might add up to this list?


In conclusion, though swimming in a circular motion might be normal for some fishes, the owners and pet takers must observe the fishes’ behaviors keenly. Always check tips on raising fishes in tanks. Check the nitrate levels, pH levels, and ammonia levels regularly to prevent poisoning and avoid parasites to live in your pet’s body. Make sure the water quality is excellent, and the environment of these aquatic animals are in the proper state.