Will Male and Female Betta Fish Fight?

Will Male and Female Betta Fish Fight?

With most species of commonly kept fish, the males and females of the species can live together. However, with most species of fish, they can also live in groups. When it comes to betta splendens, this is not the case, as they are highly aggressive to members of their own species. But are they aggressive to members of the opposite sex?

Betta splendens is the most commonly available betta species and is extremely aggressive towards other bettas. Of course, the males and females must come together at some point, otherwise, the species would die off. The answer to whether male and female bettas can live together depends on several factors, but it is possible. We will discuss harem tanks, betta breeding, betta tank size, decorations, and sibling bettas.

Harem Tanks

A harem tank is a tank that houses one or two males and multiple females. This tank type is incredibly rare when it comes to keeping bettas, but it can be successful. The minimum tank size for this type of set up is 75-gallons. This tank gives enough room for one or two male bettas to set up territories and lessen their aggression.

The number of female bettas in this set up can vary greatly, but the minimum should be seven. Female bettas will establish a hierarchy amongst themselves, and they need this number to spread out the aggression. This will prevent one or two stronger bettas killing the weaker ones.

The females will establish a pecking order separate from the male betta most of the time. However, there have been cases in which the lead female betta is more aggressive than the male betta. Most of the time, the male will sit at the top of the chain and pick his mate, but if the female is the most aggressive, she will likely be the only female to breed in the tank.

Breeding causes the male to become more aggressive than normal. In a 75-gallon tank, this is generally not an issue, as the others have room to avoid him. The young will not survive in this type of tank, as the other bettas will eat the free-swimming fry.

Dither fish, or fish used to draw aggression, are necessary for this tank set up. These fish can be anything from a school of corydoras to a school of tetras or rasboras. Tetras and rasboras would the best choice as dithers for bettas. Since bettas primarily inhabit the upper and mid-levels of the tank, their dither should as well.

Betta Breeding

As previously mentioned, bettas become very aggressive during the breeding process. When breeding bettas, the breeder must be prepared to lose one or both of their fish. At the very least, they need to be prepared for serious injuries and damage. Their most beautiful betta may end up disfigured, damaged, and no longer show-grade.

Most of the time, the female will receive most of the damage. However, this is not always the case. I even had a female that was much more eager to breed than the male, and the male ended up with permanent damage and bent fins. Either way, there will be fighting.

When breeding bettas, the breeder places a pair in a small tank with little décor. The tank is normally a partially filled 10-gallon, often holding five gallons or less. The lack of decorations means there are no hiding places or sight breaks, so aggression bettas will continue their chase.

If you are considering keeping together a single male and a single female, the chances of it succeeding poor. I have yet to see a successful tank housing a male and female betta splendens that lasted even a year. It is possible to house them together if provided enough space, decoration, and dithers.

Provided enough space, forty gallons and up, and many decorations and dither fish, it can work. However, the fish will likely want to breed in the tank, and one or the other may not be receptive. This can lead to incessant chasing and stress, and stress kills fish.

Tank Size

If you attempt to keep bettas in a tank that is too small, it will never work, even if you fill it with decorations and dither fish. Bettas need to establish their own territories, and if they do not have the room to do so, they will get rid of the intruder.

In order to safely keep a single male and a single female betta together, you will need a 40-gallon tank. You will also need a massive amount of decorations and dither fish. I recommend at least two schools of dither fish for this set up.

For a harem tank, you need a tank of 75-gallons. The tank needs multiple dither fish school and should be heavily decorated or planted.  The dither fish should be in schools of 8-12 with 2-3 schools in a tank this size. Having multiple caves and plants for bettas to hide in will assist in reducing aggression.


Decorations are vital when it comes to housing multiple bettas together. Bettas are aggressive, and there is very little that will decrease the aggression. Decorations are one of the few things that will. Bettas will chase one another, but if one is able to hide and get out of the sight of another, they will lose interest. “Sight breaks” are decorations or plants that break the line of sight of aggressive bettas, allowing other bettas to escape.

Decorations come in several forms, including plastic caves, flowers, houses, and other things found at pet stores. These should be less than half of the decorations present in aquarium. The vast majority of your sight breaks should be plants.

Plants provide large bushy barriers that fish can hide in and swim through. They provide a greater amount of security than plastic decorations. They also help reduce nitrogen compounds within the water, which lowers the number of water changes you must do.

Plastic decorations often have sharp edges, and these can easily damage a betta’s delicate fins. If you gently run a tissue over a decoration and the tissue tears, it will tear a betta’s fin. Plants do not have this problem, unless you keep hornwort in hard water.

Without decorations, bettas will be unable to escape one another, and fighting will ensue. In order to keep bettas together, you must make sure they do not fight. A single fight can signal which betta is weaker, and the weaker one will constantly be under attack.

You must keep close watch on both bettas, since fighting can ensue at any point. Just because they have gone months without fighting doesn’t mean they will get along forever. Signs of torn fins and missing scales could be early signals that the tank will fail.

Sibling Bettas

When breeders raise baby bettas, they keep them all in one tank for the first part of their lives. As the bettas grow and start to show aggression, thee breeders separate them. Some of the least aggressive bettas will remain in a tank with their siblings until sold. Sometimes, these include males.

If you want the absolute best chance for your male and female to get along, get two from a breeder that live together. If the bettas are already accustomed to one another’s presence, they are less likely to fight. The minimum tank size will still be the same, even if the breeder is keeping them in a smaller tank. Their tank is temporary, yours is not.

Finding bettas, especially male bettas, that currently live with other bettas together is rare. You will have to contact individual breeders and buy from them, instead of buying some in a store. Stores keep bettas separated, and even if they can guarantee two used to live together, they will react with aggression if reintroduced. Even if the store only separated the bettas for a few days, they will still fight when reintroduced.

The best formula for a successful tank with a male and female tank is to have a large tank, a massive amount of decorations, and dither fish. While this does not always ensure your tank will succeed, it gives you the best chance.

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