Are Goldfish Aggressive? (7 Reasons That Makes Them Aggressive)

Written by John Sawyer in Fish Species,Goldfish

Goldfish are playful animals that do not have aggressive behavior in the wild. But when placed in an artificial environment, is it possible for them to develop aggressive behavior towards their tankmates? Are goldfish aggressive? Let us discuss below:

Goldfish are non-aggressive species that like sharing space with other tankmates. However, goldfish usually turn aggressive in a situation of an overcrowded tank or insufficient food. Consider providing proper water conditions and ample space in the tank to avoid aggression in your goldfish. 

Let us dive into the article to learn about aggression in goldfish and how to avoid it. In addition to this, we would also discuss the natural behavior of goldfish.

Goldfish natural behavior

  1. Goldfish are peaceful animals that love to interact with their tankmates.
  2. Goldfish do not prefer aggression towards each other.
  3. Goldfish can thrive up to a water temperature of 75°F.
  4. Goldfish chase each other when competing for food or mating purposes.
  5. Goldfish are messy as it produces a lot of waste.
  6. Goldfish enjoy feeding on aquatic plants in the tank. Java Fern is the best aquatic plant for goldfish aquariums as it does not prefer to feed on them. 
  7. The water ph level of a goldfish tank should be 7.5
  8. Goldfish have a good sense of hearing as they can detect sounds up to 4khz with an optimum range of 500-800Hz.

Are goldfish territorial?

Goldfish are peaceful animals that prefer to interact with other tankmates. But they can be territorial if the size of the tank is small and there is no room for them to swim.

In such a case, your goldfish will try to mark its territory, leading to aggression in your goldfish.

It would be advisable to provide a big size tank to your goldfish and not overcrowd your tank so that your goldfish have enough room to swim. Therefore, doing this will help to avoid aggression in your goldfish.

7 reasons that make your goldfish aggressive?

7 reasons that make your goldfish aggressive are:

  1. Overcrowded Tank 
  2. Limited Food
  3. Territoriality
  4. Spawning 
  5. Unsuitable tankmates
  6. Stress
  7. Personality

Overcrowded tank 

Overcrowded tank is one of the common reasons for your goldfish getting aggressive. An overcrowded tank provides no room for your goldfish to swim, making them aggressive with their tankmates.

Limited food 

Limited food can also lead to aggression in your goldfish. If you are not providing enough food for your fish, they might start competing for food, further leading to aggression in your fish. 

Also read: What Do Goldfish Eat?

Territoriality 

Your goldfish can also be aggressive when it becomes territorial. 

Spawning  

Goldfish can also be aggressive while mating. When mating, male goldfish can get a little aggressive towards the female goldfish.

Also read: Can Goldfish Get Pregnant?

Unsuitable Tankmates 

Unsuitable tankmates can also lead to aggression in your goldfish. If you have paired your goldfish with aggressive tankmates, then it can lead to major aggression in the tank. 

Also read: Can Goldfish Live With Angelfish?

Stress 

Stress can also lead to aggression in your goldfish. You can discover your goldfish chasing and nipping the other tankmates due to stress.

Your goldfish can come under stress due to various reasons like poor water conditions or overcrowded tanks. 

Also read: Are My Goldfish Stressed?

Personality

Personality issues can also lead to stress in your goldfish. Some goldfish have an aggressive nature. 

Also read: Can Goldfish Live Alone?

How can you tell aggression is occuring?

You can discover aggression in the tank in numerous ways. Some of them are 

  1. Fish gets injured
  2. Hiding 
  3. Passed away fish

Fish gets injured

If you discover one or more fish injured, it indicates aggression in the tank. Injuries will mostly be in the fins or tails of your fish.

Therefore, it will be advisable to ensure that the injury is because of the other tankmates rather than any sharp objects in the tank. As any injury from the sharp object can lead to infection in your fish. 

Hiding 

If you find out your fish hiding in the corner, it indicates aggression in the tank. It is because fish prefer to hide when the other tankmates are aggressive.

But hiding does not always show aggression, as goldfish prefer to hide when sick or lonely. 

Also read: Why Is My Goldfish Hiding?

Passed away fish 

If you find a passed away fish with injuries in the tank, it indicates bullying by the other tankmates. Therefore, it would be advisable to find out the aggressive fish and remove them from the aquarium in such a case.

We want you to know that your goldfish can pass away for numerous reasons rather than fighting, like swim bladder diseases, fin rot, and dropsy. 

Also read: Why Did Goldfish Die Overnight?

How to tell if it is aggression or not?

It is normal to be confused to decide whether your goldfish is bullying or interacting with the other tankmates. However, you can conclude it by discovering some signs of your goldfish. 

  1. If your goldfish is swimming around each other rather than after each other, it indicates no aggression. 
  2. If you discover your goldfish come closer to each other and then dart away rather than chase, it indicates no aggression by your goldfish. 

Therefore, we want you to know that goldfish are peaceful animals that love to interact with their tankmates and avoid aggression.

Actions to take after you notice aggression in the tank

Here are some actions you can take after you notice aggression in your goldfish tank: 

  1. You should avoid overcrowding your goldfish tank as an overpopulated tank provide no room for your goldfish to swim, leading to aggression in your goldfish. 
  2. You should always provide sufficient food in your goldfish tank as lack of food makes your goldfish compete with their tankmates, leading to aggression in your fish.
  3. Goldfish are peaceful animals who like to interact with other tankmates, but they can be territorial due to insufficient space in the tank. Providing enough room will help to avoid aggression in your fish. 
  4. It would be advisable to keep a good ratio of male and female fish in the tank. More females with fewer males will help to avoid chasing for mating. 
  5. You should never add aggressive fishes in your goldfish tank as goldfish are peaceful animals that do not prefer aggression. Adding aggressive fishes can lead to major aggression in the tank, further leading to stress in your goldfish.
  6. You should always maintain the water condition and temperature of your goldfish tank. As polluted water and improper water condition can lead to stress in your goldfish, making your fish aggressive. 
  7. Some goldfish are aggressive personalities that do not have any solution. So it will be advisable to place the aggressive goldfish in a separate tank to avoid aggression. 
  8. You should always provide hiding spots in your goldfish tank as it helps eliminate stress in your goldfish as stress leads to aggression in your fish. 

These were some actions you should take if you discover aggression in your goldfish tank. 

Conclusion:

  1. Goldfish are non-aggressive animals who enjoy the company of other tankmates. 
  2. They usually get aggressive in some situations, like an overcrowded tank or limited food. 
  3. You should always keep a good ratio of male and female goldfish in the tank to avoid aggression. 
  4. Some goldfish have aggressive personalities that have no solution rather than to place them in a separate tank. 
  5. Avoid adding aggressive fishes in your goldfish tank, as it can stress your goldfish and also lead to major aggression in the tank. 
  6. Inadequate water temperature and poor water condition can also lead to aggression in your goldfish. 

Reference: Academic ScienceDirect

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