How Many Betta Fish Fit in a 5-Gallon Size Aquarium?

As the new owner of a betta fish, you are probably wondering how many fish will fit in your tank. Knowing how many fish are comfortable in a small tank is important.

Overcrowding leads to aggression and poor health, so it is important to consider. You want these beautiful tropical fish to be as comfortable as possible.

Bettas can live in small tanks, but five gallons of water is the minimum tank size for one betta fish. One male betta or one female betta will live in a five-gallon tank, but not as comfortably as in a ten-gallon tank.

It is really more desirable to keep your betta fish in a larger tank so they have ample space. And bettas are perfectly happy as single fish.

how many betta fish in a 5 gallon tank atf

Do Betta Fish Live Well in a 5-Gallon Tank?

There aren’t five gallons of swimming space once you have rocks, a heater, a filter, and decorations. It will crowd your fish in a five-gallon tank but will survive.

Using a smaller tank also limits the surface area of the water. This is where male bettas make bubble nests, so it is important to have enough space.

If you put another betta in, there would not be enough room to hide from one another. Bettas are very territorial and will fight to injury or death.

Five gallons is the absolute minimum size to keep a betta fish in. They are very active fish and need plenty of space.

We’ve reviewed some of the best 5-gallon tanks available here if you’re looking.

How Many Is Too Many Betta Fish?

Even two betta fish are too many in a five-gallon tank. The fish will feel crowded and become more aggressive and fight.

The water quality in your tank will suffer from having too many fish.

A five-gallon tank barely has enough water to establish a healthy nitrogen cycle. Adding another fish will overwhelm it.

This means changing the water more to keep the water parameters healthy. Adding another fish will mean more work for you and make your fish uncomfortable.

Is There Room for Two Male Bettas?

A five-gallon tank does not have room for two male bettas. They are aggressive, territorial fish and will clash, often fighting to the death.

Bettas living together need places to explore and hide. A five-gallon tank just doesn’t have enough room for the aquatic plants and rocks your betta needs.

Only one betta fish of any kind should be kept in a five-gallon tank. Crowding leads to territorial disputes and aggression.

Using Dividers in a 5 to 10-gallon tank

Some fish tank owners separate male bettas with a divider. Using a divider in a five-gallon tank would reduce the livable space too much.

Using a divider in a ten-gallon tank will enable you to have more than one betta, but they will be in cramped quarters. It isn’t really recommended to use dividers with these small tanks.

May I Keep One Female and One Male Betta in My Small Tank?

can i keep male and female betta in small tank

Putting two bettas of either sex in a five-gallon tank is not recommended, as the living area is just too small. They need plenty of swimming, hiding, and resting spaces.

Putting a female betta in with a male will just lead to fights and territorial behavior.

If you want to breed your bettas, a better size to consider is at least 40 gallons. This gives them plenty of room to hide from each other and rest.

This is where a tank divider comes in handy.

If your breeding pair is having trouble acclimating to one another, use the divider. Gradually remove it over time so they become used to one another.

How Many Female Betta Fish Should You Keep?

One female betta fish will live in a five-gallon tank by herself.

A betta sorority is five or more females. A sorority will need at least thirty gallons to provide five gallons of space per fish.

This will keep aggressive behavior to a minimum. It also helps ensure good water quality for your sorority tank.

As always, getting along depends on the behavior of the individual fish.

Keeping less than five is inviting trouble. If you have an aggressive female, she will terrorize a small group of other bettas.

When one female is aggressively dominant, it subjects the other to a life of submission and fear. They need plenty of hiding spots to escape from each other.

If you have two aggressive female bettas, they will fight until one wins. This can happen to the point of injury or death.

Observe Your Fish

It is important to observe your fish’s behavior and look for any signs of aggression. Some fish, like people, get along better than others.

An overly dominant or aggressive fish will stress out or injure the other fish in the tank.

They need to be removed from the tank. This is more likely to happen if you are keeping less than five females.

A good way to avoid these clashes is to introduce your fish slowly. Give the fish a few days to get used to the tank before you add another fish.

Some fish keepers even introduce their fish by keeping them in separate tanks at first and having them able to see each other through the glass.

What Tank Mates Are Good?

We’ve established it isn’t a good idea to keep other bettas in a five-gallon tank. So, what kind of fish species will work?

Small, peaceful fish or invertebrates will work in a smaller betta tank. Some ideal tank mates for bettas are:

  • Ember tetras
  • Phoenix rasbora
  • Dwarf rasbora
  • Mystery snails
  • Nerite snails
  • Ghost shrimp
  • Amano shrimp
  • Cherry shrimp
  • Corydorus
  • Plecos

Again, you do not want to overcrowd your tank capacity; it will stress everyone out. This will lead to poor water quality from too much fish waste.

A rule of thumb is to have one gallon of water per inch of fish. The betta needs 5 gallons just for itself.

How Do You Set Up a Small Tank for Bettas?

betta tank setup in 5 gallon tank

When setting up a five-gallon betta fish tank, choose one with a good lid. Bettas love to jump out of the tank.

Add a good filtration system for water quality. Consider an air stone to increase oxygen levels since it is such a small tank.

A good submersible heater is also a must to keep a stable water temperature.

Poor water conditions are a top cause of fish stress and illness. Regular tank maintenance is key to success.

Good water conditions

Bettas, like any other fish, need clean water to do well. A five-gallon aquarium will need weekly water changes to keep the water clean.

A minimal schedule of regular water changes would be a 25% water change weekly. Dirty water will make your betta stressed and weak, making them vulnerable to illness.


Gravel is a good substrate for betta fish, as they will not inhale it when they are bottom-feeding. Good bacteria also live in the gravel and help keep your fish healthy.

It is essential to use a gravel vacuum to clean up waste and uneaten food.


You will need a good-quality submersible heater for your tank. Bettas are sensitive to water temperature. Keep the water temperature stable between 78-80° degrees Fahrenheit (25.5-27° C).


Especially at this size tank, adding a filter is necessary. This will prevent the buildup of excess waste.

A good filtration system with bio-filter media will process out ammonia and lower nitrate levels. Remember to change your filter on time!

Live Aquatic Plants Are Great!

Enrichment, or mimicking their natural habitat, is important for bettas. Adding live aquatic plants is a superior enrichment method and lowers their stress levels.

Your betta will enjoy plants as hiding spots, resting places, and entertainment. Live plants also improve water quality and create a healthy environment.

Adding rock caves for hiding spots is also great. Setting up a tank with plenty of hiding spots is important.

Keep Tank Décor Minimal

Since you have limited space in a five-gallon tank, you must keep décor at a bare minimum.

Good Things Come in Small Packages

Setting up a five-gallon tank for your betta fish takes some consideration and care. Creating a home for these beautiful fish is easier in a larger tank but can be done in a smaller one.

Give them as much space as possible, lots of plants, and use the proper aquarium equipment, and you will have a lovely tank in which to enjoy your pet.

For more information on betta fish care, check out this page!

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Wesley Oaks has a background in web publishing and decided to combine his skillset with his enjoyment of betta fish. When he isn’t working behind the scenes for Betta Fish Bay, he’s homeschooling his kids and soaking up quality family time.

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