Why Do Goldfish Chase Each Other? (Causes and EFFECTS!)

Why Do Goldfish Chase Each Other? (Causes and EFFECTS!)

If you have pet goldfish, try to understand their behaviors and interpret them.

Do you want to know why do goldfish chase each other? Chasing is typical behavior of goldfish. They chase each other to court and bully the other goldfish.

Let’s jump to the topic to learn more about goldfish chasing.

Why Do Goldfish Chase Each Other?

Have you ever wondered why do goldfish chase each other? The chasing happens potentially for mating and their aggressive behavior. Besides, they run after each other for their territory, incompatible tank mates, overcrowding, and lack of food. So be aware of the underlying issues to be addressed.

Make sure to provide your goldfish with compatible tank mates and a peaceful environment. 

Some Reasons for Chasing Each Other

When goldfish chase each other, It is a sign for many reasons. It can be their normal behavior, or maybe they are too stressed out.

There are two main reasons. Breeding is the most common reason, and aggression is another one.


Suppose male goldfish run after a female goldfish that is the cause of courting. When male and female goldfish attempt to mate, the male goldfish chases the female goldfish.

It seems like they are harassing each other. But this is not harassment as goldfish is a docile fish.

Different types of goldfish have particular spawning behavior. When goldfish mature, they prepare for mating under the proper water condition with proper nutrition.

When they are going to spawn, all the male goldfish gather around the female goldfish and start chasing the female one. Finally, the male goldfish violently push the female goldfish to release the eggs. 

When the female goldfish drops out all the eggs, the male goldfish fertilizes those eggs. As the female goldfish drops many eggs, it needs more than one male goldfish to fertilize the eggs.

The female goldfish may lose a couple of scales because of the attack of the male goldfish. But it doesn’t stress out the female goldfish too much through the breeding process.

The female will recover within one week. Although, while mating, male goldfish chase the particular female, they don’t chase more than one female at a time.

See how male goldfish chase the female goldfish during the breeding process-


Goldfish is a territorial species. Usually, goldfish are peaceful fish, but they become aggressive when their territory is under threat.  

If your goldfish don’t get enough space to move that time, they become stressed out and chase after each other.  

If you don’t keep any hiding place in the tank, the goldfish won’t find their territory in the empty tank and will start fighting each other. So make sure to keep some little areas in the tank for goldfish to find their territory and take a rest. 

If you don’t add any hiding place, they can’t defend themselves from the attack of other goldfish. 

Incompatible tank mates 

Goldfish can live with the same type of goldfish with similar habitats.

Make sure to keep the same type of goldfish together to avoid fighting. Some goldfish breeds are a little bit aggressive and tend to hurt the weaker goldfish. Make sure to keep the different breeds separate. 

Comets and common goldfish swim fast and fancy goldfish move slowly because of their long flowy fins. 

Comets and common goldfish will feel attracted to the long fins of fancy fish and may nip the fins. Fancy fish move slowly, so the comet goldfish can quickly nip their fins.

See how aggressive goldfish chase each other-


Overcrowding also causes chasing each other. Goldfish are large fish. It needs ample space to roam peacefully in the tank.

If you keep your goldfish in a small tank, they may feel stressed and start to chase each other and nip the fins of other goldfish.

For peaceful movement, you must ensure a minimum of 30 gallons tank for one goldfish and add 10 more gallons for each goldfish.

Weak companion

Goldfish are calm fish, but they are not that kind. It tends to bully its weak partners. Generally, the strong goldfish dominate the small and weak ones, suffer from any disease, or are physically injured. 

Goldfish can rip the skin of another goldfish, and you will be able to see the bone of the fish.

Watch the video to see how strong goldfish rips the skin of another goldfish-

Lack of food

Goldfish eat a lot and eat anything that fits in their mouth. Even they eat their eggs as well. During feeding time, goldfish chase each other—especially the strong one who chases the weak one to have food.

Goldfish can be aggressive if they are not fed properly. If any of them starve, it may make them stressed, so they start to chase each other. 

Suppose you don’t feed your goldfish regularly. In that case, they may suffer from different diseases and can be attacked by the strong goldfish.


Goldfish is a schooling species. Sometimes they chase each other to interpret with the other fish. Sometimes they move with their groups and chase each other to avoid boredom. 

They play but don’t hurt each other by chasing.

How to Prevent the Chasing of Goldfish?

Chasing is a common phenomenon of goldfish. But sometimes, it becomes severe. It may cause sickness and even death if you don’t stop it.

Make sure to follow some precautions to avoid chasing goldfish to give them tranquility. 

  1. Don’t keep comets or common goldfish with fancy goldfish. 
  2. Make sure to add hiding places for each fish to control the chasing behavior. You can add logs, caves, and driftwoods as hiding spaces. 
  3. Try to keep average fish to avoid fighting as strong fish attempt to damage the weak ones.
  4. Maintain a pecking order before choosing the goldfish.
  5. Add enough plants to stop chasing.
  6. Make sure to feed all goldfish regularly to keep them healthier. 
  7. Separate the aggressive goldfish in a quarantine tank. 
  8. Keep your goldfish in a large tank.
  9. Put the compatible tank mates.

Are Goldfish Chase Each Other in a Pond?

In ponds, goldfish don’t chase each other because of overcrowding, lack of space, and inadequate food. 

Usually, male goldfish chase female goldfish in the pond when they are about to courtship. They start breeding when the temperature is cold to warm. During breeding, the pond gets foamy and smells like dead fish. However, it is not a problem and will go away after some time.

Watch the video to see how goldfish do mating in the pond-


If you are still thinking, why do goldfish chase each other? The reasons for this behavior! Then in this article, you will discover it–

  • The chasing happens potentially for mating and their aggressive behavior.
  • Besides, they run after each other for their territory, incompatible tank mates, overcrowding, and lack of food.
  • Be aware of underlying the issues to be addressed.

Finally, now you are acknowledged with the facts, why they chase each other and how to control it.

Frequently Asked Questions

Q1. How Do You Know if Your Fish Are Fighting or Playing?

You can quickly identify whether your fish is fighting or playing.

Suppose you can see any marks on your goldfish’s body and fins. In that case, you can easily understand that they are fighting because of their aggression.

Q2. How Can You Understand if Your Goldfish Is Happy?

Suppose you notice that your goldfish is swimming throughout the tank with their tank mates and eating regularly. In that case, that means your goldfish is happy.

Q3. How Can You Understand the Difference Between Male and Female Goldfish?

You can easily understand the difference between male and female goldfish–

  • Male has big flowy fins compared to male goldfish, and female one has small fins. 
  • Relatively, male goldfish are large.
  • Female goldfish have a softer and rounded body.

Q4. What Do You Feed to Your Goldfish Every Day?

It would help if you fed flakes and pellets to your goldfish 2 to 3 times a day. In addition, you can provide vegetables, fruits, and live foods as a supplement twice a week.

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