How Many Bettas in a 20 Gallon Tank?

You can keep only 1 male betta in a 20-gallon tank. With multiple hiding places, you can keep 5 female bettas together in a 20-gallon tank as a sorority, but there is still the potential for fighting.

The betta, or betta splendens, is a small labyrinth fish with a wide array of bright colors and fin varieties, making them some of the most striking freshwater fish in aquarium hobby. But there is one thing that makes bettas hard to keep; usually only one betta can be kept in a tank.

Bettas have a reputation for being fighters that have to live solitary lives, but occasionally there are exceptions to the rule. With a good number of hiding places and an adequately sized tank, a female betta sorority isn’t out of the question.

How Many Bettas in a 20 Gallon Tank?

The amount of bettas that can be kept in a 20-gallon tank depends on the gender of the betta. All bettas are aggressive and territorial to some degree, which is why it’s so difficult to house them together. Even the females will want to fight to defend the areas of the tank they believe belong to them.

Male bettas are difficult fish to keep, not because of their tank or feeding requirements, but because they have been bred over the years to be aggressive towards other bettas. This sour temperament can also spill over into aggression with other types of fish, and some male bettas won’t tolerate living in a community tank.

If you really want a tank with multiple bettas, you’ll need to look into female bettas instead of males. Female bettas share the bright colors with their male counterparts but have shorter fins and a slightly more sociable temperament. That being said, each fish is an individual, and some females will tolerate a sorority environment better than others.

If you’re new to betta ownership, or you just aren’t sure how to set up your 20-gallon tank for multiple bettas, only keep 1 betta. 

Two Red and Blue Betta Fish

How Many Female Bettas Can Live In a 20 Gallon Tank?

For new betta owners, it’s recommended that you stick to 1 betta in your 20-gallon tank until you are more experienced with the specific temperament that bettas have. If you’re a more experienced betta keeper and are ready to have a tank with multiple bettas, then it’s time to look into the all female betta sorority tank!

What is a Betta Sorority?

A betta sorority is the name for a group of female bettas kept together in one tank.

Since female bettas display less territorial aggression than males, they can be kept together in the right environments, but a betta sorority isn’t an easy undertaking.

If you choose to keep a betta sorority, you need to be prepared to remove the fish if the circumstances don’t work out and the fish continue to fight.

To avoid territorial disputes and bullying between your female bettas, there are a few rules that must be followed:

  • Keep, at minimum, 5 female bettas. You want enough fish that they won’t focus on one other female to bully.
  • Provide plenty of places to hide. This includes plants and caves where the bettas can get away from each other if tensions are running high.
  • Have, at minimum, a 20-gallon tank. Anything smaller than 20 gallons and there won’t be enough space for the bettas to separate from each other.
  • Introduce the bettas at the same time. If they are added at different times, there is a chance the existing female bettas will gang up on the new one.

How Many Male Bettas in a 20 Gallon Tank?

As we mentioned before, only one male betta can be kept in a 20-gallon tank. The only exception to this is if the tank is divided. 

The minimum size for a betta tank is 5 gallons, so in a 20-gallon tank, you can potentially use dividers to section off 4 appropriately sized areas for 4 male bettas.

Dividers for a 20 gallon betta tank must be:

  • Non-transparent, so the males can’t see each other. Even if the male bettas can’t get to each other, being able to see the other males will have them in a constant state of stress.
  • Permeable enough for water to flow freely throughout the tank. The draw for separating a tank into 4 betta areas is that you will only need 1 heater and filter, but in order for this to work, the water must be able to flow freely through the dividers.
  • Taller than the waterline. Bettas can jump, so it’s important the dividers reach above the waterline so they can’t cross over into one of the other 4 areas.

Is a 20 Gallon Tank Big Enough for a Betta Fish?

Yes, a 20-gallon tank is big enough for a betta fish. The minimum tank size for a betta is 5 gallons.

One falsehood that many betta owners hear is that bettas don’t need more than a single gallon. In reality, 5 gallons is the minimum tank size for a single betta. A 20-gallon tank is a substantial size for a betta, and it gives them plenty of space to explore.

Bettas are adventurous, curious fish, and the more space and things they have to keep them stimulated during the day, the better. With a 20-gallon tank, there is plenty of space for live plants, stone caves, and other betta-appropriate tank additions.

If you have to choose between a 20 gallon tall and a 20 gallon long, always go with the 20 gallon long. Bettas will appreciate the extra horizontal swim space, and since they are labyrinth fish and need to breathe from the surface, having a shorter swim to the top is beneficial.

In Conclusion

Unless you are keeping a sorority of female bettas, or splitting your tank for multiple males, only 1 betta can be kept in a 20-gallon tank. Bettas can be aggressive and territorial, and don’t do well sharing a tank with other bettas.

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