Skip to Content

How Many Betta Fish in a 3 Gallon Tank? (Read This First!)

There is a popular myth that betta can live in a small tank but is it true? How many bettas can live in a 3 gallon tank? The answers may surprise you. Keep reading to find out if you can keep bettas in a small tank like 3 gallons and some essential information you may want to know.

How many betta fish in a 3 gallon tank?

Keeping any more than one betta in a small tank like 3 gallons is not suitable. 5-gallon tanks are ideal for them considering cost and fish comfort, while 10 gallons or more is better. If you keep more bettas in a small tank, their lifespan will be reduced.

Bettas can live in a small place. You may see bettas are kept in small cups in shops. But that is not the right thing to do. They can just survive in a small place. But they need space, suitable temperature, and hiding spots to live a comfortable life.

Let me explain in more detail. Bettas are tropical fish that originated from Southeast Asia. They live in shallow water and can take oxygen from the air. When the dry season arrives, the water dries, and the bettas get trapped into small mud holes with little water.

They survive there until the water level rises. As bettas can respire from the air, water oxygen level does not affect them. We always want to provide our pets with a comfortable and happy life. But the case is different when it comes to fish.

However, although bettas can survive in a small tank, it is not ideal. A 3-gallon tank can inhabit only one betta fish with proper care.

The problem with a 3 gallon tank is the nitrogen cycle does not work well. For proper nitrogen cycling, you will need at least a 5-gallon tank.

Due to the small space in a 3-gallon tank, it is difficult to maintain correct water conditions. After setting filers and substrates like rocks and sands, a little room remains for the fish, which is not entirely ideal but somehow workable for one betta.

Can betta fish live in a 3 gallon tank?

A single betta can live in a 3 gallon tank. But it will not have the best life there. Suppose you live in a small bathroom with food and care. You can live there for years, but it will never be your home. It will be more like a cage.

Similarly, smaller tanks than required are not appreciated. However, If your betta is small in size, it can stay there comfortably. Adult bettas may have some problems adjusting there, but they will still grow and live if you do everything right.

Is a 3 gallon tank big enough or good for a betta?

Three gallons is the minimum size for a single betta tank but not good enough. 5 gallons is decent tank size. If you want to breed your betta, a 5-gallon tank is essential.

Male bettas must keep alone, while you can keep 2-10 female bettas in a tank. For that, you will need a bigger tank for them. Find out why a 3-gallon tank is workable but not the best for the bettas.

Bettas need space:

Bettas need space to swim and move around. They can live alone happily, but a small tank will make them inactive and unhealthy. Although, a 3 gallon tank is not that tiny. You can keep a betta in a 3 gallon, but regular maintenance is necessary.


Like most fish, bettas need a constant water temperature. But in a 3 gallon tank, it is pretty hard to maintain. When water volume is less, the water temperature can change rapidly with the environment.

Water quality:

For bettas, water quality also needs to stay constant and dramatic changes in water can be dangerous. But in a small tank, maintaining the water quality is hard. Fish waste and wasted food make the water dirty.

How long can a betta fish live in a 3 gallon tank?

A betta fish can live up to 2-3 or even five years if you provide everything they need. But a 3-gallon tank with no heater and filter, bettas will not live longer than one year.

Betta tank water needs to stay within 76-82 degrees F. Cold water is not suitable for them as they are tropical fish. A sound filtration system is also vital for bettas. A betta diet should contain a high amount of protein content as omnivores.

How many female betta fish in a 3 gallon tank?

You can keep only one female betta in a 3-gallon tank. It is not possible to keep even two female bettas in a 3-gallon tank, as the water condition will go wrong even soon, and bettas can become territorial as there is little space for them.

However, if you have a big enough tank, you can keep up to 10 female bettas together. Female bettas are usually not aggressive if the tank condition is suitable. Male bettas are incredibly territorial and should always be kept alone.

How many betta fish can fit in a 3.5 gallon tank?

3.5 gallon tank is suitable for one adult betta. If you have small bettas, you can keep them for some time but not permanently. But even a pair of bettas can not live comfortably in a 3.5 gallon tank.

If you want to keep more than one betta, get at least 5 gallons of water, while 10 gallons is best. For adding one extra betta, add 3 gallons more water for the fish. Bettas love to swim in shallow water, so deep tanks are not good for them.

What fish can I put with a betta in a 3 gallon tank?

A very few fish can live with a betta in a 3 gallon tank. The reason is 3 gallon tank is already a bit small for the betta. It is not ideal for increasing any more members in the small tank.

But if you really wish to, you can keep two pairs of cherry or ghost shrimp, maybe a couple of assassin snails.

But if you have a bigger tank, you can keep a list of fish with female bettas. Here is the list:

  • Ghost shrimp
  • Guppies
  • Kuhli loaches
  • Cherry shrimp
  • Cory catfish
  • Neon tetras
  • Ember tetras

How often should I clean and change water in my 3 gallon betta tank?

A 50% water change is needed once per week for a small tank like three gallons. However, this is too much water change for bettas, but you will have to do it anyway to maintain the water quality.

For a bigger tank of 5 to 10 gallons, little water change like 20-30% is enough for bettas. You should also siphon the fish waste once a week.

Final thoughts

You can keep only one betta in a three-gallon tank. Male bettas always require a separate tank, so if you have a small tank, it is better to get one male betta. Add a sponge filter and heater to maintain water quality and temperature for a healthy, long-living betta.