Whether you’ve owned betta fish your entire life or just recently started keeping them, at some point you’ll wonder or be asked the question: Why do betta fish fight?

There are a bunch of reasons why these pugnacious fish fight each other, but the history behind why betta fish are so aggressive dates back centuries. Betta’s were originally discovered in Southeast Asia in the 1800s. They were brought from their natural habitat in rice paddies and puddles, back to local towns by those working in the fields.

The betta fish and their aggression led to keepers fighting them, betting on the matches, and specifically breeding them for increased aggression. Matches became so widespread the King of Siam regulated these fights by taxing them. This genetic aggression still exists today.

Fighting Myth

Betta fish will not always fight to the absolute death. Most of the time they won’t even get close to that point, unless they’ve been selectively bred for aggression or are trapped in a small tank with nowhere for the less dominant betta to hide. This is especially true for betta splendens or the most common betta’s sold as pets.

Bettas will often damage their opponents scales, gills and tails by nipping and thrashing about. Those injuries, along with infections caused by stress, could, however, kill a betta after fighting. Deliberately making betta fish fight is cruel.

Why Do Male Bettas Fight Each Other?

Male betta fish fight each other because they are incredibly territorial. In the wild, bettas have miles of rivers and paddies to swim through when it’s not drought season. When one male enters another’s territory, the two may show aggression, but a fight may not happen with plenty of room to retreat.

During a fight, the two male bettas will fan out their fins and puff out their gills (flaring) to make themselves look twice as big. This act is done to intimidate and scare off the opponent. If that doesn’t work, they’ll nip at each other until one of the two retreats.

In a tank with no plants or other places to hide, it’s inhumane, to leave them in a tank together. NEVER put two males together without a partition separating them and their visibility to one another.

Male bettas will also fight for food. Betta fish will typically eat as much as you can feed them in captivity. In the wild, however, they have to either find or hunt down their food to survive. In those scenarios, when two males come together, there is no pack mentality, but simply a need to survive.

Males will also fight each other to protect their nests and eggs. When a male betta is ready to mate, he’ll blow a bunch of bubbles on the water’s surface creating what is called a bubble nest. Once his masterpiece is complete, he’ll wait for a female to come along and notice. Any threat to his chances at reproduction will ignite his protective instincts.

Do Female Bettas Fight Each Other?

Females are generally less aggressive than their male counterparts, but they can still be very territorial and will fight one another. They can cohabitate peacefully in groups of female betta fish, known as sororities. Females will generally be aggressive with other females for a little while in a sorority until a natural pecking order is established.

For example, in a 20-gallon tank with 9 female betta fish, one will establish herself as the alpha and the others will submit to her and form smaller packs of their own. Provided no new betta fish are added, disrupting the ecosystem, they will likely live peacefully without incident.

When creating a sorority of females, it’s best to have several in the group and plenty of space for them. A sorority must contain at least 4-5 females. Some females may still be too aggressive for the sorority life.

Larger habitats are best, allowing each betta enough room to claim her own space. Dense plants and hideouts provide betta fish with a safe spot to hide from bullying and to relieve stress. Never add a male to a sorority tank.

Why Do Male and Females Fight Each Other?

Male and female betta fish will fight with each other too. They should never be housed together except during mating and separated immediately after. It’s common for females, for example, to eat the eggs during spawning, so a male will chase off and defend against this behavior.

Males are the ones who place the eggs in the nest and care for them until hatching. They will do whatever it takes to protect their offspring.

Males and females generally fight for the same reasons males fight males and females quarrel with other females. They are territorial fighting fish and don’t cohabitate well with each other.

How Long Do Betta Fish Fight?

If two male bettas find each other in the wild, both will fan out their fins and puff out their gills to look as large as possible. If that doesn’t scare one of them away, the two will nip at each other until one decides to retreat. In most cases, a betta fish fight may last a couple minutes or end immediately.

Fights will last much longer in bettas that have been selectively bred for aggression and usually end with one betta either very injured or dead. Reminder, this is animal cruelty and should never be done in captivity.

Do Bettas Fight Other Fish?

Male and female betta fish are usually kept in small containers at pet stores because of their territorial aggression. These temporary containers are meant to isolate them from each other and other fish. Every betta fish has a different personality and level of aggression. They are also perfectly content living on their own with the right care.


Bettas will fight other fish if:

  • The tank is too small for a community ecosystem
  • There are not enough spaces to hide
  • The other fish resembles a betta fish
  • The other fish is brightly colored
  • The other fish has long fins
  • The other fish is aggressive too


Tank mates should be avoided for inexperienced keepers, but if you want to learn more, visit our tank mate recommendation page.

Avoid tanks smaller than 10 gallons for a community tank with other fish species. You need to provide enough space for everyone to cohabitate without aggravation and overcrowding.

About The Author

Founder & CFO (Chief Fish Officer)

Founder of bettafish.org and betta fish enthusiast. With over six years of betta husbandry experience, I wanted to create a place that was educational and fun for other betta keepers. Stick around, you'll learn a lot!

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2 Responses

  1. Linda Hindman

    Hi Bryan, I’ve been keeping fish for about 20 years. I’ve had everything from ocros (please forgive my spellng). to rainbow fish. About two years ago i got 4-5 sailfin mollies, I now have at least 20 fish, I want to get most of them all males or all females. In the mean time I got a couple of rainbow fish. I bought new decorations and hidy spots. Everyone is getting along very well, by the way I have a 55 gallon tank. I heard somewhere you could add 1 or 2 bettas they are so beautiful. I wanted to get one more, do you think they’d be ok? I have a dark blue one, id like to get bright gold one or deep red.


    • Bryan

      Hey Linda, 20 years that’s awesome! A 55-gallon tank is large and if you have it setup with lots of plants and hiding spaces, it’s possible but not a great idea in my opinion. It really depends on the temperament of each fish and betta. You could try it out while monitoring it very closely and keeping a separate tank or cup close by in case you needed to remove one of them fast. You could also consider splitting the tank in half with a divider so that each side has 22.5gallons and could have a betta fish on each without them coming into contact with one another.


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