How Many Rasboras In A 10 Gallon Tank?

A 10-gallon tank is too small for housing rasboras permanently. In theory, you could keep 2 or 3 rasboras in a 10-gallon tank, but because these fish are very active swimmers, they need more tank space to stay happy and healthy. 

However, because rasboras are schooling fish, it is best to keep them in groups of at least 6. A 20-gallon tank is required for that number of rasboras. This article discusses the recommended tank size for rasboras and explains why it is important for these fish to have enough space in their tank.

Can You Keep One Rasbora In A 10 Gallon Tank?

There is a general rule that aquarists use to figure out how much tank space you need for various fish: for every inch of fish, you need two gallons of space.

So, considering rasboras reach about 2 inches in length, a single adult rasbora, in theory, needs 4 gallons of tank space. By this calculation, you could keep one rasbora in a 5-gallon tank or two rasboras in a 10-gallon tank.

However, this rule does not account for the behavior of various fish species.

Rasboras are active little fish that mostly occupy the middle and top levels of a tank. They are a species of fish that school together. It makes them feel safer when they are in a group.

Therefore, while 4 gallons per rasbora is the minimum recommended tank space, it is best to be a little more generous and give each fish more room in the tank.

You could keep a single rasbora in a 10-gallon tank, but because they are social fish, it is rather cruel to keep one alone.

School of Harlequin Rasboras with Angelfish in Background

How Many Rasboras Can You Keep In A 10 Gallon Tank?

You can, theoretically, keep two rasboras in a 10-gallon tank. However, this is the bare minimum amount of tank space, and it is not necessarily a good idea to keep only two rasboras.

Two rasboras should not be kept in a 10-gallon tank permanently. However, if you want to breed rasboras, you can keep a breeding pair in a 10-gallon tank temporarily.

How Many Rasboras Should You Keep?

It is not ideal to house just two or three rasboras in a tank, and you should never keep a single rasbora. Expert aquarists recommend getting at least 5 to 7 rasboras.

Because rasboras are schooling fish, they are happiest when they have a group of other rasboras around them. In a large enough tank, schools of 25 rasboras make a striking display.

What Tank Size Do You Need For A School Of Rasboras?

You need at least a 20-gallon tank for a small school of 6 rasboras. If you want to keep a slightly larger school of 8 to 10 rasboras, you need a 30- to 40-gallon tank. A large shoal of 20 to 25 rasboras will need at least a 55-gallon tank.

The more space you can give your rasboras, the better. These fish are happiest and healthiest when they have plenty of room to swim around with the rest of their school.

Why Do Rasboras Need A Spacious Tank?

Fish in overcrowded tanks or tanks that are too small suffer from stress. If fish do not have enough space to behave as they naturally would, their stress levels negatively impact their lifespan.

Rasboras can live for surprisingly long, considering their small size. Under ideal conditions, rasboras can live for 5 to 8 years!

All good aquarists aim to maximize their fish’s life expectancy by minimizing their stress levels. Providing enough tank space for rasboras is key to preventing stress.

Rasboras live the longest when you keep them in large schools. They have evolved this shoaling behavior to avoid predation.

Rasboras feel most relaxed in a big shoal because there is safety in numbers. But keeping a large group of rasboras requires a large tank.

Another reason why you need a spacious tank for rasboras is that these fish like to have lots of aquatic vegetation in their tank. It gives them hiding places and surfaces they can lay their eggs on.

It is a good idea to get an extra-large tank for your rasboras so that you can plant the tank with lots of plants and still leave large open areas for the shoal to swim around.

Can Rasboras Live In A Community Tank?

Rasboras are ideal fish to keep in a community tank. They are peaceful little fish, so they can live with other docile species, like cory catfish, danio, dwarf gourami, tetras, and bettas.

However, you must be wary of overstocking your community tank! Overcrowded tanks are detrimental to the fish’s health.

Rasboras in a community tank need double the amount of space they need in a single-species tank. Therefore, a 10- or 20-gallon tank will never be sufficient to house rasboras along with other species.

How Large Do Different Rasbora Species Grow?

The name rasbora actually refers to a whole genus, or group, of different species. There are dozens of different species of rasboras.

The various species do not all grow to the same size when mature. When you are calculating how much tank space you need for a group of rasbora, you must take the species into account.

You can keep a greater number of small rasbora than larger rasbora in a tank.

The most common types of rasbora for aquariums are:

  • Harlequin rasbora – reach 2 inches in length
  • Clown rasbora – grow up to 3 inches
  • Chili rasbora – only reach 0.7 inches long
  • Black line rasbora – grow 2.5 inches long
  • Dwarf rasbora – only reach 1 inch
  • Emerald eye rasbora – reach 1.6 inches in length


Rasboras should be housed in groups of at least 5, but ideally 7 to 10. Therefore, a 10-gallon tank is far too small for a shoal of rasboras. These active fish need more space to swim around.

You could, theoretically, keep two rasboras in a 10-gallon tank, but this is not the ideal situation for these fish. They need to live in a school to feel safe. A 30- or 40-gallon tank is more appropriate for a group of 7 to 10 rasboras.