How Many Chili Rasbora in a 5-Gallon Tank Is Ideal?

Alison Page

Alison Page


how many chili rasbora in 5 gallon

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Chili rasboras are gorgeous nano fish that are perfect for life in a small, single-species tank or as part of a community setup.

These delightful little fish are peaceful and get along with other fish and inverts, and they’re relatively straightforward to care for, although they do best in a mature aquarium.

So, how many Chili rasboras can live in a 5-gallon aquarium?

Ideally, you want to keep these fish in a school of not less than six, although five is better in such a small tank to keep the fish healthy.

If you fancy keeping these brightly colored tropical fish, keep reading to learn more about their care!

How Many Chili Rasboras Can Live in a 5-Gallon Aquarium?

As a general rule of thumb, you can keep one inch of fish per gallon of water so that you can keep five or six Chili rasboras in a 5-gallon tank setup.

That provides enough space for lots of hardy plants, decorations, and a few tank mates.

Chili Rasbora Origins

Chili rasboras or Bororas brigittae are beautiful nano tank fish that do best when kept in large schools, where they feel safe and secure.

These fish native to Southwestern Borneo in Indonesia are also sometimes called Mosquito rasboras because of their habit of eating mosquito larvae.

It’s the males’ bright ruby-red color that makes them an aquarium favorite, but they’re peaceful and easy to care for, too.


Chili rasboras are micro fish that love to school in the middle and top areas of the water column, although they will venture lower in search of food.

Although these are very active fish, they can be quite shy and tend to hide away if not kept in large enough groups. I once kept a group of five rasboras in a community aquarium and hardly ever saw them because they spent most of their time hiding among the mature plants and decorations.

Eventually, I bought another five Chilis to add to the community, and they almost immediately appeared much happier, schooling together around the tank and creating a gorgeous display of vibrant, sparkling color.

Tank Conditions

The crucial thing to know about keeping Chili rasboras is that they need stable water chemistry to thrive. So, be sure to avoid fluctuations in the water parameters and temperature in your tank.

Tank Size

As mentioned above, you can keep these stunning fish in a 5-gallon aquarium in groups of a maximum of five.

However, if you can stretch to a 10-gallon tank, you could keep up to 12 Chili rasboras, and a 20-gallon aquarium could accommodate a large school of around 15 fish.

These tranquil fish are easily spooked, so I always recommend keeping them in a tank with a tightly fitting lid or cover slide, just in case they jump out.


Chili rasboras show their best colors when kept in a heavily-planted aquarium with a sandy, dark substrate and lots of dense real plant cover, including some floating varieties. Java moss is an excellent plant that works well in a rasbora tank.

The natural environment for these fish is blackwater pools and streams under the rainforest canopy, so aim for dappled shade and use Indian Almond leaves or peat to create those tea-colored, blackwater conditions.

Since these can be shy fish, it’s a good idea to use decorations, such as coconut tunnels, driftwood, and caves, to provide the fish with plenty of hiding places.

Water Parameters

Chili rasboras are tropical fish that enjoy soft water with a low pH. So, you want to provide the fish with a water temperature between 68°F and 82°F and a pH in the range of 4.0 to 7.0. The water hardness should ideally be 3 to 12 dKH.

To ensure the water conditions are ideal for the rasboras, be sure to test the water regularly using an aquarium water testing kit.


The water movement in the rasboras’ natural habitat is slow, and they don’t appreciate a strong current in the aquarium, so you might need to buffer the current with plants and decorations or use a redirection attachment on your filter outflow pipe.

These fish need pristine water conditions to thrive, so you’ll need to install a powerful, efficient filter system in your tank. You must also carry out weekly water changes and keep on top of filter system maintenance tasks, replacing the media periodically in line with the manufacturer’s guidelines.

Tank Mates

how many chili rasbora in 5 gallon

Chili rasboras get along very well with other small, peaceful species of fish and small invertebrates like shrimp and snails.

You should avoid keeping these tiny rasboras with larger fish and aggressive types that might outcompete the rasboras for food or even view them as a food source.

Good tank mates for Chili rasboras include:

Other types of rasbora species can also make good tank mates for the Chili rasbora in a community tank.

As mentioned earlier in this article, you must keep at least six Chili rasboras together if you want to enjoy their best colors and behaviors.

However, the more of these delightful fish you have space for, the better, as a school of 20 or even more makes a fabulous display in a single-species type of setup!

What To Feed Chili Rasboras

Chili rasboras are technically omnivores, although I find that they prefer a mostly meaty diet. My rasboras enjoy a varied diet of tropical fish flakes, frozen and freeze-dried bloodworms, and brine shrimp.

Variety in their diet encourages the best color and health in the Chili rasboras, but you must take care not to overfeed them since their tiny size leaves them vulnerable to sickness if they eat too much. In addition, overfeeding causes problems with the water quality in the tank, which is very bad news for the rasboras.

Finally, remember that these are tiny fish with very small mouths, so you’ll need to make sure the food you offer them is small enough for the fish to eat. I usually crush fish flakes into a fine powder and chop up large bloodworms for my rasboras.

Final Thoughts

I hope you enjoyed our guide to how many Chili rasboras can live in a 5-gallon aquarium. If you did, please take a moment to hit the share button above!

Ideally, Chili rasboras need to live in schools of at least six individuals. These tiny fish rely on safety in numbers to feel secure and safe, so the more you can keep the better. We recommend keeping five or six fish in a 5-gallon tank, although if you have the space for a larger aquarium, you can keep more.

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