Are Betta Fish Aggressive? (Signs Of Aggression In Betta Fish)

Betta fish are also known as siamese fighting fish, which hints at their temperament. Also, it is necessary to know about the temperament and requirements of the fish when planning to add them to a community tank or in a separate tank. So, Are betta fish aggressive? Let us find out.

Betta fish are aggressive, especially male ones. Male bettas are more territorial and will fight with other fish and each other to defend their territory and food. Keeping only one male betta in a tank is recommended, as two male bettas will end up fighting until one dies.

This article will also discuss what triggers aggression in bettas and how we can lower aggression in bettas. So, let us get into it.

Betta fish temperament

Betta fish, also known by the name of “siamese fighting fish,” are aggressive fish.

They have an aggressive nature and can fight and even kill the other fish present in their tank.

Keeping two male betta fish in the same tank will end with both fish fighting until one dies.

Male bettas are more territorial and fight with other fish to defend and protect their territory.

Also, in their natural habitat, they get limited food supplies, so they have to fight for resources as they need a high amount of protein to survive.

Also read: How Many Betta Fish Can Live Together?

Are betta fish aggressive towards each other?

Betta fish are aggressive to each other, especially males.

Male bettas are territorial and fight each other to defend their territories.

Also, male bettas fight and show aggression to impress female bettas for breeding.

They use their beautiful colors and aggression to attract female bettas towards them for breeding.

Male bettas form a bubble nest at the water’s surface to attract female betta.

They also protect the eggs inside the nest from other fish at any cost to show themselves as a strong and potential mate to female bettas.

Female bettas are more social and less aggressive than male bettas but can show aggression when kept in inadequate living conditions.

You can keep female bettas together in a group. When you keep them together, the cohort is known as a sorority.

Are betta fish aggressive to their tankmates?

Betta fish can be aggressive towards their tankmates if they see any threat or competition.

Any fish that are more colorful and bigger than your betta fish, then your betta will try to nip and fight with them.

Fishes like goldfish, angelfish, gouramis, cichlids, and tiger barbs should not be kept with your betta fish.

These are some of the best tankmates of your betta fish:

  1. Guppy
  2. Neon tetras
  3. Kuhli loach
  4. Snails
  5. Shrimps
  6. Plecos
  7. Cory catfish

Adding non-compatible tankmates to your betta fish tank will result in aggression and fighting.

What are the signs of aggression in betta fish?

These are the signs which will help you detect aggression in your betta fish:

  1. Your betta fish will expand their gills to look broader and more intimidating. 
  2. Your betta fish will nip the fins of their tankmates, which will cause harm to the opponent. Fin nipping can result in fin rot, which can make the fish suffer from a life-threatening condition.
  3. Your betta fish will spread their fins along with gill flaring to look bigger. They do this to scare off the opponent and win the battle without getting physical.
  4. When nothing is working, they will get physical by ramming their bodies together to hurt each other and show aggression.
  5. Having missing fins, a red body, and minor injuries is also a sign of aggression. Your bettas may be fighting when you are not looking at them, and in such cases, minor injuries will be the signs of aggression to look for.
  6. Change in their behavior is also a sign of aggression in your betta fish. Your betta fish will look more dominant and intense when they are aggressive.

What causes aggression in betta fish?

Betta fish are known to be an aggressive creatures. They are also known as siamese fighting fish because of their aggressive nature.

In their natural habitat, they have to fight for food resources because of food scarcity.

Also, aggression for establishing their territory, for food, and for attracting females is common in many fish species.

Inadequate water parameters and conditions also trigger aggression in your betta fish.

Keeping a bigger and more colorful fish than your betta in its tank will trigger aggression on them.

In captivity, they can also show aggression while feeding. They do this to protect their food from other tank mates.

How to make my betta fish less aggressive?

Ensuring all these things will make your betta fish less aggressive:

  1. Avoid keeping more than one male betta fish in the same tank.
  2. Provide your betta fish with enough living space.
  3. Avoid adding non-compatible tankmates of your betta fish to their tank.
  4. Provide your betta fish with stable and good water conditions.
  5. Provide your betta fish with plenty of hiding spots.

Avoid keeping more than one male betta.

As we discussed above, keeping more than one male betta fish together in a tank is not advisable.

Keeping them together will end up fighting until one of them dies.

Male bettas are more aggressive and territorial and will not allow the other male betta to live in their territory.

Provide enough living space.

Everybody thinks that betta fish live in a small place in their natural habitat, so they will not require much space in captivity, but this is not true.

Betta fish require ample space to live and swim comfortably.

You must provide at least 5 gallons of space per betta fish. 

When keeping betta fish with other tankmates, make sure to keep them in a large size tank.

For example, if you want to keep corydoras, snails, shrimps, and betta fish together, you must first see the fish’s space requirement.

To avoid overcrowding, you must follow the one-inch one-gallon rule, which means one inch of fish per gallon of water.

Add some gallons extra as plants, substrate, and other decors will acquire some of the space.

After that, you have to look for the minimum number of fish to be kept. Some are schooling fish and require a group of thrive. 

Also read: How Many Betta Fish In 5-Gallon Tank?

Avoid adding non-compatible tankmates.

Bettas are aggressive and territorial fish, and keeping them with other aggressive and territorial fish will end up in aggression and fighting.

Betta fish will not like to live with fish that are more colorful and bigger than them.

Consider adding fish that are peaceful and smaller than your betta fish.

Ensure good and stable water conditions.

Providing your betta fish with ideal and stable water conditions is necessary to prevent stress and aggression.

Betta fish are very sensitive when it comes to water parameters and conditions.

They require a clean water condition with stable water temperature.

Provide your betta fish with a water temperature between 78-82 °F.

Add a heater to your betta fish tank to ensure stable and adequate water temperature.

We recommend using the Fluval M200 Submersible heater for your tank.

The ammonia and nitrite of your betta fish tank should be 0 ppm, whereas nitrate should be below 20 ppm.

Also read: Ideal PH Level For Betta Fish?

Provide hiding spots

Providing your betta fish with plenty of hiding spots will help lower their aggression.

Your betta fish require hiding spots to relax and hide when they are weak.

There are plenty of options when it comes to hiding spots. Some of them are terra cotta pots, sunken ships, and caves.


Bettas are known to be aggressive creatures, and this is why they are also called “siamese fighting fish.”

Male bettas will be aggressive towards each other when kept in the same tank and will fight until one of them passes away.

Keeping two male bettas, bigger and more colorful fish than bettas, inadequate water conditions and parameters will trigger aggression in your betta fish.

Providing your betta fish with large-size tanks, compatible tankmates, and adequate living conditions will lower their aggression.

Conclusion: NCBI, ScienceDirect, Wikipedia

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