Why Do Betta Fish Fight? (+ Do Bettas Fight Other Fish)

Wondering why betta fish fight? This guide is for you!

The betta fish is genetically predisposed to antagonism, which it displays through constant fights with its counterparts and other fish.

But why do betta fish fight so much?

Bettas fight because they are instinctively wired to do so. But this is not the only reason. Your betta fish fights to assert dominance over its territory. It flares its gills and fins and turns aggressive if stressed by hunger, poor living conditions, and trauma.

Seasoned betta keepers know to read the signs that show their betta fish is about to start fighting. They know that when the betta is about to fight, you have to take quick action to avert a catastrophe.

Fortunately, there are measures you can take to stop bettas fighting among themselves or fighting other fish species.

betta fishh fight

Why Do Betta Fish Fight?

Bettas have a short fuse because of centuries of evolutionary conditioning. Besides, these fish are easily triggered to aggressive behavior by fluctuations in the environmental conditions.

Anything that can go wrong in the aquarium is reason enough for your betta to display its aggressiveness.

Here are some key reasons your betta fish is likely to fight:

#1 – Protecting Their Territory

Bettas are territorial by default. Animals that display territorialism are not social; they like keeping their spaces to themselves.

In the wild, bettas are happy to lead solitary lives. However, a male betta will fight another male to the death to get him off his perceived territory.

However, such fights are less common in the wild than in aquariums. This is because bettas in the wild have miles and miles of marshland, rivers, ponds, and rice paddies to share.

There’s enough space for everyone.

The space in a fish tank is rather restricted, and bettas will fight more frequently to safeguard their perceived territory.

Regarding safeguarding his territory, the male betta will fight off bettas and other fish alike. Male bettas are particularly aggressive towards bright—colored fish species.

#2 – Predatory Instincts

Bettas in the wild are usually at the top of the food chain, and they’ll fight to retain this dominant position.

Because of centuries of genetic coding, bettas know nothing about submission. They are predisposed to be predatory.

This means a betta fish will hunt and fight as he pleases and won’t entertain another betta or fish trying to interfere with him.

When a betta is brought to the aquarium, he is still wired as a predator. So he’ll readily fight at the slightest excuse.

#3 – Fight for Food

Betta fish are incredibly motivated by hunger pangs to fight. Nothing stresses a betta and makes him more aggressive than a lack of food.

Whenever this creature misses a few meals, his predatory instincts kick in, and few would dare to stand in his way.

He will swim around the tank angrily, lashing out at other fish and taking their food.

You can stop your betta’s predatory tendencies from being triggered by timely feeding him the right food.

#4 – Overcrowded Environment

As noted earlier, bettas don’t like sharing their space. Therefore, they are readily agitated when other bettas or fish species come too close to them.

Bettas in an overcrowded tank are more likely to fight than those in a spacious one. This fish needs space to flex its fins and gills and let everyone know he’s the boss.

Being in an overcrowded tank makes a betta fish feel confined and limited. This automatically triggers its fighting instincts.

#5 – Heightened Stress Levels

Even a relatively docile betta fish turns aggressive when stressed. A stressed betta behaves in a manner that indicates you don’t know your pet that well.

A stressed betta becomes angry and is quick to lash out. While some bettas go into hiding or lie at the bottom of the tank to show stress, most resort to fighting.

To a betta fish, fighting is the best expression of discontent, anxiety, and distress.

As such, you need to keep an eye out for factors that cause stress in the aquarium. These include bad food, dirty water, loud noises, and hostile tank mates.

#6 – Excess Energy

Betta fish get restless with pent-up energy. This is common with healthy animals, especially if they have been feeding well but with few activities.

Your betta may fight as a way of releasing this pent-up energy.

If you notice your betta swimming exciting over, below, and beside the objects and other fish in the tank, know that a fight will likely go down.

Because of the excess energy, your betta looks for a reason to start a fight. But, unfortunately, it doesn’t take much to give this fish the reason he needs.

The presence of the other fish in the tank is reason enough for him to unleash his fury.

You can forestall or prevent this behavior by furnishing the betta tank with enough toys.

#7 – Small Swimming Space

Bettas in the wild are used to the vast swimming areas of ponds, marshes, and shallow rivers. These fish have miles upon miles of slow-moving streams to explore.

Bettas in your home or office aquarium will fight because of the limited swimming space. The limiting space stifles their natural curiosity to explore and master their world.

This problem is worsened if you make your betta live in a cup or a fishbowl. A betta is meant to live in a 5-gallon fish tank or bigger.

To make your betta happy and healthy, provide him with lots of water to swim and play. Swimming and playing are some of the ways your betta uses to relieve stress whenever they feel agitated.

#8 – Protecting Their Eggs

After the female betta has spawned its eggs, it is the role of the male to protect them until they hatch into fry.

While some males choose to incubate the eggs in the mouth, some bettas use bubble nests. Many fish species consider betta eggs and delicacy and will try to steal them from an inattentive male.

Vigilant betta males will fight to the death to protect the eggs from predators.

#9 – Disease and Trauma

Disease and injury make betta fish stressed. These factors make your pet feel vulnerable, and he hits back by fighting other fish species that cross his path.

It’s easy for other fish in the wild to escape the wrath of an injured betta. However, the ones in your home or office aquarium may not be so lucky.

Find out the illness or trauma your betta fish is dealing with and provide him with the proper relief.

#10 – Fighting Bettas

In some cultures, bettas are bred and trained to fight each other. These bettas are made to fight to entertain crowds, who pay handsomely to watch the fights.

If you come across this breed of betta fish, you’ll immediately realize they are highly aggressive. However, these bettas don’t need any tangible reason to start fighting other bettas or fish species.

They have been intentionally bred to fight for the sake of it!

How Do Bettas Fight?

A betta fight is one of the most terrifying things a new keeper can witness their bettas do. It is a bloody affair that usually ends in the death of one or both belligerents.

To fully understand what this fight looks like, you need to refer to the sport of Betta Fish Fight.

This is an illegal activity in the US and Europe. However, it is a favorite pastime in South East Asia and other parts of Asia.

In a Betta Fish Fight, intentionally bred bettas are put in one tank and made to fight to the death.

The bears are matched on type, age, and size and made to fight until one or both bettas lose their fins and die.

This gory fight can last minutes or hours. It is appalling to watch, and its popularity is declining even in countries where it was held in high regard just a few years ago.

When you think of the concept and outcome of this fight, you wouldn’t want your better fish to be involved in any kind of fight.

How to Know Your Betta Fish is Aggressive

By nature, all bettas have a certain level of aggression. However, some are highly aggressive and become violent at the slightest push.

How can you tell your betta is an aggressive troublemaker?

Fins and Gills Flaring

Betta fish flare their fins for a number of reasons: some good and others bad. For example, a male betta may flare to display its beautiful colors to attract a potential mate.

Also, a betta fish may flare to indicate agitation and the willingness to fight other fish around him.

You should be concerned when your betta fish keeps flaring. Find out what inspires this behavior and constructively deal with it before it gets out of hand.

Making some simple but crucial changes to the tank conditions may be all that’s required to restore the situation to normalcy.

Your betta will flare its fins and gills if it feels threatened by its tank mates. However, if you help him resolve this matter, he will calm down and resume his everyday life.

The betta fish uses flaring as a way of warding off potential competitors. This should be your cue to separate this betta from the other fish before they escalate the situation.

Biting Other Fish

Bettas that bite other bettas or other types of fish are likely to be a fighter. They get agitated quickly and don’t take long to turn on their perceived rivals.

Biting can cause serious injuries, leading to stress and unwarranted aggression. In addition, a bite from a betta fish will severely compromise the victim’s health.

If your betta displays tendencies to bite the fins of other fish, it’s time to segregate him.

Lunging at Other Fish

Lunging indicates your betta’s intent to start a fight. Some signs point to the aggressiveness of this fish, but not its intention to fight.

For example, flaring shows the betta is aggressive and willing to fight. But, this fish has not committed to the fight until he lunges.

A betta that keeps lunging at other fish will eventually initiate a fight that could turn fatal. Therefore, the best course of action is to put this betta in another tank before the situation worsens.

Staring at Other Fish

A betta that intends to fight another fish will start encircling it in a stare-off. But, of course, the betta could also stay still in the water, with its eyes unwaveringly fixed on its target.

This is a display of aggression. Your betta wants to intimidate the other fish, and this will end in a fight unless you intervene.

Chasing Other Fish

An aggressive betta keeps chasing other fish around the tank. This betta is very restless and looking for a chance to make the lives of the other fish miserable.

Relocate such a betta before he wreaks havoc in the lives of these fish. The harassed fish are likely to be stressed, opening a whole can of worms.

Do Male and Female Bettas Fight?

Male bettas are, by default, more territorial and aggressive than their female counterparts.

This means that if there’s going to be any fighting between these genders, it will likely to initiated and fueled by the male.

That said, male and female bettas have a high chance of living together harmoniously.

This is because, in the presence of the male, the female tends to be submissive, which deflates the male’s desire to assert himself.

However, this pair can display aggression toward each other, ranging from mild to severe, depending on the circumstances.

For example, if the male and female bettas are put in a cramped space and forced to fight for resources, they may engage in a serious fight.

This fight will be so severe that it could leave the female seriously injured or dead. On the other hand, if the male is smaller and weaker than the female, she may have the upper hand.

The male betta also tends to chase the female around the tank to initiate spawning.

When she lays the eggs, the male puts them in bubble nests, where he stands guard as he waits for the eggs to hatch.

During this period, he turns aggressive toward any fish that comes near the eggs, including the female that laid them.

How Do You Stop Betta Fish from Fighting?

It is in the interest of every betta fish owner to keep these animals safe and secure in their tanks.

You need to be prepared to stop bettas from fighting because you never know when you could have a fighter in your home aquarium.

Timely intervention to stop this fight will not only save the other fish, but save the life of your pet betta as well.

So, what are the best tactics to stop your betta from fighting?

Relocate the Other Fish

This is the simplest, most logical, and most effective way of handling a betta fighter. Once the betta sees that the perceived rival is gone, he will calm down.

Eliminate the Stressors

Another way of handling this situation is by getting rid of the cause of stress. If it is bad food, change the diet and give your betta fish the food he deserves.

In the same way, clean the water, ensure the tank is big enough, and check the temperature and pH levels.

Divide the Tank

If you must keep the two fish in the same tank, use an opaque divider, so each fish has its own compartment.

Ensure that each compartment is well equipped with everything the betta needs to lead a healthy, meaningful life.

Train Behavior Change

You can discourage your betta from fighting through positive affirmation. This involves rewarding good behavior to encourage it.

However, this method needs much time to accomplish, and is resource intensive. Nevertheless, with the right effort and commitment, it is doable.

Do Bettas Fight Other Fish Species?

Bettas will fight other bettas and other fish species aggressively. This is true to this animal’s nature. Being a territorial fish, your betta dislikes sharing space with ANY fish.

However, betta fish seems more tolerant of some fish species than others. He” readily accepts some species as tank mates and rightly rejects others.

Here are some fish species your betta fish is unlikely to accommodate in his tank:

  • Slow-moving fish – the betta fish will easily catch up with this fish and engage them in a fight.
  • Small fish species – the betta consider tiny fish and fry food. If they can fit in his mouth, he’ll devour them.
  • Long-tailed fishes – because their fins resemble those of bettas, the betta fish sees fish with long-tailed fins as rivals.
  • Brightly-colored fish are likely to be the most obvious targets of betta fish because they compete with his bright colors.


Being fiercely territorial, bettas fight to assert dominance over their perceived and actual rivals. They also become very aggressive in protecting their sources of food.

Your betta fish is sensitive to changes in the environment. Any difference in the water and food quality, temperature, and pH level will likely set him off.

You can help your betta by ensuring his living conditions are up to standard. Keep this fish well-adjusted and balanced in the tank; he’ll be less likely to turn aggressive and start fighting.

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