How Do Betta Fish Fight

How Do Betta Fish Fight?

Betta fish are well known for being highly aggressive fish, fighting most other fish they encounter, and every other betta they encounter. In fact, another name for them is the “Siamese Fighting Fish” due to their aggressive nature. Even during breeding, the male and female can both sustain lethal injuries from one another. But they look like small, harmless fish, so how do they even manage to wound one another?

If you have ever seen two betta fish near each other (not in the same tank) but just able to see one another, you will see how aggressively they act. They will try to do everything in their power to break through to the other betta and attack them. Bettas normally attack the same way they kill prey; with their teeth. They have strong jaws and sharp teeth; a good combination for both fighting and hunting.

In this article, we will discuss why betta fish fight, flaring, fighting, injuries, and keeping betta fish together.

Why Do Betta Fish Fight?

Domesticated betta fish have long since been breed to fight aggressively, similar to a pit bull or rooster fights. While bettas in the wild will still have spats over different territories, it is not nearly as aggressive as domesticated bettas.

While this is partly due to the breeding history of bettas, another factor is the small spaces that pet owners keep bettas in. In the wild, bettas live in large bodies of water and rivers spanning several miles, if not more. In captivity, they often only have 1-3 feet of space.

This is a massive difference since most bettas hold a territory that is about three square feet. If they are not provided with more than this area, two male bettas will not be able to exist in the same body of water. They will feel like their territory is constantly being invaded, and they will try to scare the other one out, resulting in a fight.

Even if one does not wish to fight, they also do not have the ability to run away or go elsewhere. This forces both of them to fight, often until one dies, effectively removing them from the winner’s territory.


The vast majority of bettas will flare before resorting to actual fights. Flaring is when bettas stretch out their fins and gill plates to make themselves look as big as possible. It is an intimidation tactic used as an attempt to avoid an actual fight.

In the wild, if two male bettas encountered one another, they normally flare, and the weaker one will leave without a fight. The winner of the “flaring contest” is not necessarily the one that looks bigger. Brighter coloration and intact fins can be enough to make up for smaller, less impressive fins.

However, as previously stated, bettas cannot run from one another in captivity. Instead, they are forced to fight due to the lack of space. However, you will likely still see bettas flaring at each other, both males and females.

That being said, they can hide for short periods of time if you have a heavily decorated or heavily planted tank. This will drag the fight no longer but will give you a better chance of separating the fish before it is too late.

Even if you have only one betta, you will see them flare at one point. If they see their reflection and get worked up, or even if they get angry at you for some reason, they will flare. While flaring is a good way to determine tail type and keep your betta active, they should not be allowed to flare for more than 5 minutes per day, as it will stress them out.


Here we will tell you what to expect during a fight. Depending on the circumstances, a fight may last just a few minutes, or several days. The factors include the disposition of the bettas, the gender of the bettas, and how well decorated the tank is.

Bettas have unique personalities, and these play a huge role in a fight. While this is incredibly rare, you may encounter two male bettas who have no interest in fighting one another. On the other hand, the two bettas may tear one another to shreds in a matter of minutes.

Most bettas are somewhere between these two possibilities, meaning fights normally last half an hour to several hours. Female bettas tend to have longer, more drawn out fights, while male bettas have shorter and more aggressive fights. This is primarily due to females being more likely to run away than males.

During a fight, a betta’s teeth are the primary weapon. They normally attack the fins of the other fish first, as this both weakens them, and makes them appear less attractive to females. They will continue to attack, biting the sides of the other betta, the head, eyes, gills, and so on, until the betta is severely injured or dies.

Once one betta attacks another, they will both begin fighting ferociously. This means both bettas can easily end up severely injured or dead. An unfortunate aspect of bettas is that they will continue to fight until they can no longer move as long as they still perceive a threat.


If you can catch the fight early (assuming there was an accident with a divided tank or similar, and that you have two separate places for the bettas) you first need to separate the bettas. Next, examine them for injuries. If it was early on, the injuries will primarily be around the fins.

Watch closely over the next few days for septicemia, or blood poisoning, which is a fast-moving infection. If you do not see red lines going up the fins, your fish will likely recover just fine. Do extra water changes to keep the water clean and add an Indian Almond leaf to help prevent infection.

If you were not able to catch the fight early, the injuries may be severe enough to warrant euthanization. If your fish is unable to swim at all and has either very rapid or very slow gill movement, their chances of recovery are very low.

You can treat moderate injuries that same way that you would treat mild injuries. Be sure to watch closely for infection and take great care in keeping the water fresh and clean. Avoid stressing your fish, as this can negatively impact their immune system. It makes it more difficult for them to recover and fight off infections.

Keeping Betta Fish Together

After reading this, keeping bettas together sounds like and awful idea; and most of the time it is. However, it is fully possible to house bettas together as long as you take the proper steps and precautions.

If you want to keep a group of female bettas, or a sorority tank, it is best to start with a tank of 40 gallons (though smaller is possible) and at least 7 bettas. Female bettas are capable of establishing a complex hierarchy. They will have small fights for the first few days to a week, but will then maintain the hierarchy until one becomes ill or passes, at which point there will be more fights.

As previously mentioned, it is possible to keep two male bettas in a tank of at least 75-gallons. It is also possible to add a large group of female bettas to that same tank as well, between 7-10. However, in all tanks containing multiple bettas, you will need a heavily planted or decorated tank, and dither fish.

Dither fish can be almost any other fish but are normally a schooling fish. They are used to draw aggression away from other fish, or to make skittish fish more comfortable in their environment. In this case, the dither fish will help dissolve fights between bettas, as they normally distract bettas from one another.

In conclusion, betta fish fight with their teeth, tearing the fins and flesh of other fish until either that fish is dead or they can no longer fight. They primarily attack other bettas, as they view them as a direct threat to their territory. However, it is possible to help a betta recover from a fight and to keep multiple bettas in one tank.

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