Betta Fish Fights: Why (& How) They Can Get Aggressive

Betta fish fighting
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Last Updated: February 27, 2023 by Flora Gibbins

Are you wondering why Betta fish fight? We empathize with your concerns as Betta fish fighting can limit your aquarium and community tank options. Can you keep betta fish tankmates? What happens if more than one betta fish is put in the same tank?

Here we explain why Betta fish in the first place. It also seeks to cover the subject from the point of view as a collector who wants to understand the culture of Betta fish fight club activities and how to train your Betta fish to fight.

Betta Fish Fighting

Why Do Betta Fish Fight?

Betta fish, also known as Siamese Fighting Fish, are aggressive by nature. A major reason that males fight one another on-site is that they have become incredibly territorial in the wild. Their natural habitat often has minimal food resources that the fish must compete for and will guard their territory’s food supply avidly.

Male Betta fish fight instincts will also kick in as they protect their bubble nests and the eggs within them. Males hope to attract females with the nest they have built, and other males in their territory may challenge their chances of successfully breeding.

Another answer to ‘why do Betta fish fight’ is intimidation. They can be startled by movements, especially from fish with long fins and larger tails. Of lesser concern, but still worth noting, is that brighter colors can produce this reaction as well.

Stress can be another factor when it comes to male Betta fish fighting. Changes in water conditions can stress your Siamese Fighting Fish. Another stress factor would be changing of aquarium decorations that might alter an established territory.

While male Betta fish are known to fight each other on-site, they can also act aggressively towards female Siamese Fighting Fish as well. That is why many Betta fish keepers will not house females and males together except for when they are trying to breed them.

In the case of female vs. male, the flaring gills and fins that the male displays may actually be courtship. Females can be aggressive with each in a community tank until a social order has been established. Once the order in the sororities is understood, the female Betta fish are usually peaceful, especially the Betta Imbellis when compared to their male counterparts.

How Do Betta Fish Fight?

Betta fish fighting will usually start with two males flaring their gills and fins in order to look more intimidating. In some cases, this will be enough, and one fish will retreat from the other.

If the display does not work (which is often the case in smaller aquariums), the Betta fish fight will escalate to nipping. Your males will circle each other, nipping at each other’s fins and tail. This will continue until one male retreats if they have room to do so.

A Betta fish fight may last only a moment, or it might last for a couple of minutes. While generations of inbreeding has reduced the aggressiveness of some store-bought fish, they will still aggravate each other in most cases. Fish that have continued to be bred for Betta fish fighting will exhibit high levels of aggressive behavior no matter what the circumstances are.

Do Betta Fish Fight To Death?

In some cases, Betta fish fighting is not lethal. Non-lethal combat happens more often in tanks with plenty or hiding places as well as ample room.

In other scenarios, the males will duel until they have injured their opponent. This may also be non-lethal if the engagement is broken off in time.

Many times, however, two male Betta fish fighting in a tank can result in a fight to the death. Their natural aggression, as well as centuries of breeding to perform in a Betta fish fight, often make duels between two males a fight to the death.

Do Male And Female Betta Fish Fight?


In short, yes. However, as mentioned previously, some behaviors that appear aggressive may actually be signs of courtship. Males will flare up to attract a female for mating, so that should be kept in mind as you observe the pair in your tank.

Males will be aggressive towards females outside of mating and you should consider keeping the two sexes separate if you are not mating your Siamese Fighting Fish.

Do Bettas Fight Other Fish

Again, the short answer is yes. If the other fish that you keep with your Betta fish share male Betta characteristics, it is very likely that they will attack the other fish.

Therefore, make sure that you are selective when selecting tank mates like goldfish for your male Siamese Fighting Fish. Avoid species with long fins and large tails. Fish that lack these characteristics might make suitable tank mates for your Betta and promote a peaceful community tank.

How To Avoid Fighting In Your Betta Tank

Keeping only one male housed in the tank is a great way to reduce fighting, for the reasons mentioned previously. Avoiding tank mates with long fins and tails, or bright colors has also been mentioned as a way to reduce fish battles. Are there other ways to reduce Betta fish fighting instincts?

One of the major considerations for you will be the size of the aquarium. Betta fish will tend to be less aggressive if they have plenty of room to carve out their territory. More room will also keep other fish from continuously swimming in that territory once it has been established.

More room also provides these fish with the room that is needed for retreats if a Betta fish fight begins. Larger fish tanks offer more room for hiding places as well. Bigger aquariums are more stable, a factor that reduces stress from fast-changing water conditions.

You should also provide plenty of hiding spaces for the Betta as well as the other fish in your aquarium. Hiding spaces allow the fish to feel more secure and will reduce their stress levels. They can also help to divide the tank space while offering areas for the fish to explore, keeping them distracted so that they are not focused solely on each other.

There are other aggressive fish species in the tropical aquarium hobby, and the more aggressive species can agitate or pick on your Betta fish. Housing your Siamese Fighting Fish with non-aggressive fish species will also lower their natural aggressiveness.

How To Make Betta Fish Fight


By answering why Betta fish fight, you probably have a fairly good idea about how to get two Bettas to fight each other. Keepers that want to provide a fight club atmosphere while protecting their fish will often keep two or more males in the same tank with clear dividers that allow them to see one another. The same effect can be produced by keeping separate aquariums next to one another.

Siamese Fighting Fish are intelligent and easy to train. Many enthusiasts know the fact that they can train their Betta fish to follow their fingers or to take food from their hands. This intelligence allows you to be able to condition and train Betta fish fighting habits.

One technique is to house the fish next to one another as described above. You can also use a mirror which allows the fish to see itself as it moves along in its tank. These actions will keep the Betta fish alert while allowing it to exercise natural display instincts.

Betta fish fighting instincts will also be at higher levels after males have built their bubble nests. They are living at higher aggression levels during this time and will respond more aggressively than normal.

Healthy fish also make the best Siamese Fighting Fish. Establishing healthy and stable water conditions should come before you train your Betta fish to fight. This includes a well-filtered water column as well as proper ph and temperature levels.

Limiting hiding spaces and keeping a more wide-open aquarium will increase your Betta’s alertness and promote more aggressive displays. Smaller fish tanks increase their territory in space provided and will make them more active also.

Reasonable fight club conditions can also be created by competing fish of similar age and size. Smaller Betta fish will retreat more readily from larger Bettas. As you train your Betta fish to fight, just remember that they are naturally aggressive and perform best when they are in good shape.

Wrapping It All Up

As their name implies, Siamese Fighting Fish (Betta fish) are highly territorial, making them naturally aggressive. Food and mating are major factors for their aggressiveness, which can be directed at females as well as other fish species.

Providing plenty of space and hiding places, as well as carefully selecting tank mates will reduce fighting. Of course, aggressive behavior can be increased with conditioning and training, as these are intelligent fish.

If you have any questions, please feel free to comment!

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