Female Betta Fish

How to Keep Female Betta Fish from Killing One Another?

One of the most common misconceptions about betta fish is that you cannot keep them together. Another common misconception is that two females can be kept together, or only females can be kept together. In fact, all of these statements are incorrect, and unfortunately, the truth is a good bit more complicated than this.

In order to successfully keep betta fish together, it is best to start with a group of female betta fish. They establish a hierarchy by fighting, so there will be torn fins and missing scales, and if done incorrectly, you will have dead fish. Luckily, it is possible to keep them together and only experience minor injuries by providing enough tank space and bettas.

In this article, we will discuss keeping two bettas together, tank size, hierarchies, harems, and non-hybridized species.

Two Bettas Together

Whether or not it is two males or two females, keeping two bettas together will always result in one dead fish and one injured fish, or possibly two dead ones. One betta will always be more dominant than the other, and this one will seek to show that dominance.

In a group setting, the dominant one can simply show that it is the boss and keep the others in check. However, since there is no group setting in this situation, only a one on one, the dominant one wants the other one OUT of their territory.

Since there is no “out” of the tank, the dominant one will continuously attack the weaker one until it is dead, thus removing it from the territory. There are unique circumstances in which this does not happen, but you generally need a 5- or 6-foot-long tank in order to achieve this.

Even when it comes to wild bettas, which are much more peaceful and sociable, it is best to keep more than a pair, unless it is a same sex pair. For betta Splendens, the commonly sold species, this is not possible.

Tank Size

One of the biggest factors in keeping female bettas together is tank size and set up. The tank needs to be at least three feet long, though longer is better. The average territory size of betta in the wild is a square meter or about three square feet.

However, this only applies to male bettas. Female bettas do not often establish a territory in the wild, but swim around through many different territories, each belonging to a different male, before choosing a mate then moving on.

On the other hand, female bettas do establish small territories in aquariums, smaller than that of a male’s. You do need at least three feet of space in order to have enough room for 5-7 female bettas, which is the minimum number needed for a sorority. Since it is difficult to introduce more bettas, it is best to start with a higher number in case one or more dies during the hierarchy establishment.

The most successful tanks with multiple bettas happen in 55-gallon tanks or larger, generally up to a 75-gallon tank. The 55 is a great size to start off with, and while a 20 long can work for 5-7, you have a better chance of success in a 55 with 7 or more female bettas.


The crux of successfully keeping female bettas together in the hierarchy. Without a hierarchy, you will have continuous issues until all the bettas die. If you have an imbalanced hierarchy, such as the kind you would see with two bettas, the outcome would be the same.

You need at least 5 females (though 7 is better) in order to establish a proper hierarchy. Otherwise, the strongest one or two will kill the weaker one or two, then turn on each other. The issue with five is that it is not uncommon to lose one or two bettas when they are first fighting out the hierarchies, and then you would be left with a dangerously low number of bettas.

They do establish a hierarchy by fighting, and it gets very ugly for the first week or so. It is best to add tannins as a preventative for infection and do extra water changes to ease their recovery.

If you have only a 20 long, it means that you generally do not have enough room for many dither fish. In a 55-gallon, you can have several schools of dither fish, which are fish that will draw some of the aggression of the bettas.

The dither fish will help distract the bettas from one another, and in a 55-gallon, you can have over 10 female bettas and 5 schools of dither fish, spreading out the aggression over a large area.

However, there will come a point in time during which one of the bettas will pass. Once this happens, all of them will fight and reestablish the hierarchy, and this can lead to the deaths of multiple bettas and the fall of the sorority. The more bettas and dithers you have, the less likely it is that this scenario will occur.


A harem is a tank that has multiple female bettas and one or more male bettas. You need at least a 55-gallon to maintain this setup, as the male betta will need three square feet for his territory. In a larger tank, it is possible to have two or more males.

For this setup, it is likely that you will have some spawning action. Luckily, the eggs and babies will not survive long, due to the number of fish, as bettas do eat the fry of other fish in the wild and will recognize the betta fry as food.

The main issue with spawning is aggression. Betta fish are already highly aggressive due to selective breeding making them aggressive enough to kill one another on sight, but during spawning, they become even more aggressive.

The male defends the nest and will constantly try to fight any other betta he sees. This sometimes draws him away from the nest, and during this time away, other bettas will try their best to eat the eggs and fry.

This often ends the spawning behavior in a day or two, instead of the normal 1-2 weeks that a male will defend the nest and fry. It is very unlikely that any fry will survive, especially when you consider dither fish as well.

Once two bettas start spawning, it is very difficult to get them to stop, so provide extra decorations and hiding areas if two of the bettas begin to spawn. They may start to spawn as frequently as once a week, and without plenty of hiding areas, this will become a major issue.

Non Hybridized Species

The commonly sold betta has been selectively bred and hybridized for beautiful colors and aggression. While it is commonly recognized as the species Betta Splendens, it has also been hybridized with Imbellis, Smaragdina, and recently, Raja (for the king bettas).

When it comes to keeping the pure species, they tend to be much more peaceful. In fact, Imbellis means peaceful in Latin. These bettas have not been bred for aggression and are much more accustomed to the presence of other bettas.

These bettas can often be kept together regardless of sex, but keeping females together is very easy. If you give 5-7 females a 20 long, it is likely that you will not see any fighting at all besides the occasional flaring.

The best way to keep a successful sorority is to keep wilds, as they are not as prone to aggression or fighting. The males often simply flare at one another (aside from when they are spawning), instead of fighting, unlike Splendens.

In conclusion, female betta fish can be kept together only if the tank is large enough and if there are enough females to establish a successful hierarchy. Though it is possible for females to begin a ferocious fight after the death of one in the hierarchy, this can be minimized by a multitude of dither fish and a large tank.

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