Can You Keep Rasbora in a 5 Gallon Tank? How Many?

If you’ve got a spare 5 gallon aquarium laying around (and a love of rasboras), you might be wondering if any rasboras will work for the thing.  (And if so, how many you can fit inside.)

A 5 gallon aquarium will hold a population of 6-8 Chili Rasboras or 5-6 Pygmy Rasboras.  You can also hold a population of 6-8 Strawberry Rasboras.  Due to the small size of the 5 gallon aquarium, you should avoid putting larger types of Rasbora, such as neons or Harlequin Rasboras.

Let’s discuss more about what type of setup you need to have to accommodate rasboras in your nano tank.

Best Types of Rasbora for a 5 Gallon Tank

If you want to keep rasboras in a 5 gallon aquarium, you need to start off by looking for types of rasbora that stay smaller than 1″ long.  The smaller, the better.

Mosquito Rasbora (Boraras brigittae) | Source: Deposit Photos

Here are a few species of nano rasbora that will work for a 5 gallon aquarium.

  • Least Rasbora (Boraras urophthalmoides)
  • Strawberry Rasbora (Boraras naevus)
  • Chili Rasbora AKA Mosquito Rasbora (Boraras brigittae)
  • Pygmy Rasbora (Boraras maculatus)
  • Phoenix Rasbora (Boraras merah)
  • Galaxy Rasbora (Danio margaritatus)

There may be more out there, but these are the most common ones.  

(Also, if you can swing a 10 gallon, that would make life a lot easier for you in the long term, but I’m going to assume a 5 gallon is all you have and not harp on about it.)

Keep in mind that you want to keep at least 6 of the same type of rasbora in an aquarium together so that they can school.  Because of this, you will want your aquarium to be a single species tank.

Strawberry Rasbora | Source: Deposit Photos

How Many Rasboras Can You Keep in a 5 Gallon?

Due to the small size of the 5 gallon aquarium, you won’t be able to keep a lot of rasboras, even though they stay small.

You should be able to keep any of the above types of Rasbora in a population of 6 in a 5 gallon aquarium.  Least, Strawberry, Phoenix, or Chili rasboras should be comfortable up to a population of 8.

I wouldn’t go above 8 for any of them.

Galaxy Rasbora | Source: Deposit Photos

Here is the breakdown in table format:

SpeciesHow Many?
Least Rasbora6-8
Strawberry Rasbora6-8
Chili Rasbora6-8
Pygmy Rasbora5-6
Phoenix Rasbora6-8
Galaxy Rasbora5-7

You can add some small snails in as well (think pond snails, bladder snails, ramshorn snails, or malaysian trumpet snails – no mystery or nerite snails) to keep things clean on the bottom of the tank.

I would strongly advise against keeping shrimp, other species of fish, or anything other animal in the aquarium with them.

How to Set Up a 5 Gallon Rasbora Aquarium

The first step starts with purchasing your aquarium.  Assuming you don’t already have one, you want to look for an aquarium that is as long as possible.

Dwarf rasbora, Pygmy Rasbora, Boraras maculatus | Source: Deposit Photos

Rasboras need a lot of space to swim back and forth in, so getting a landscape (long and short) aquarium is going to be a much better investment than getting a portrait (tall and skinny) tank.

You also are going to need to keep things as stable as possible in your tank.  As you might expect, this means weekly water changes.  But also, here are a few extra things you’ll want to do:

1. Set Lights on a Timer

Set up a timer so your light turns on and off at the same time every day.  Most aquarium lights (except the fluval spec V) can just be plugged into a $10 smart plug from Walmart to do this.   This will let you control your aquarium light cycle to reduce algae.  In addition to reducing algae, this will give your fish a regular schedule of light and dark.

2. Plants

Plant as many plants as you can in your aquarium to absorb toxins in the water.  Hardy plants like Java Fern, Java Moss, Anubias, Crypts, and floating plants will work best for this, but are by no means the only plants that will work.

Crypt Wendtii | © Tiny Underwater | License: CC-BY-4.0

3. Decorations

Make sure your fish have places to hide to avoid stressing them out.

Whether you go for natural hiding places like mature plants that provide plenty of cover, plastic decorations (which may cause brown algae), or the overturned coconut tunnels with plants glued to the top, you want to make sure your fish feel safe in your aquarium.

You don’t want them to feel like they are out in the open constantly at risk of getting eaten

4. Feeding

You’ll want to make sure you learn how to feed them properly to avoid waste.  Chili rasbora and several of the others on this list only feed out of the middle of the water column, meaning you’ll want a food that stays floating in the middle for as long as possible to avoid food buildup on the bottom.

5. Cycling

This should go without saying, but make sure your aquarium is fully cycled before you start using it.  The last thing you want to do is set up your aquarium and drop your fish in the same day.

You can get pure ammonia from online fishkeeping stores to do a fishless cycle, or you can transfer filter media over from a mature aquarium you already have.

If you absolutely can’t wait, at least get some of the instant cycling stuff to put in with your fish.  It’s not perfect, but it is better than nothing.


You can definitely keep rasboras in a 5 gallon aquarium.  It may not be the optimal setup, but you can be successful with it as long as you go into it with a plan.

You’ll want to make sure you choose the right species of rasbora (one that ideally stays .8″ or less), plant out your tank as much as possible, and stay on top of water parameters to keep your fish healthy.

Avoid keeping large rasboras, and avoid putting anything else in the aquarium with your rasboras.

Do this, and you’ll be well on your way to keeping a beautiful little aquarium.