Chili Rasbora (Boraras Brigittae): Complete Care Guide

The Chili Rasbora is a tropical freshwater fish that has held the attention of the aquarium community for quite some time.

These fish are beautiful, cute (so tiny!), and easy to care for. The fact that keeping them doesn’t require a lot of experience makes them a very approachable species!

Despite all this, it’s important to have a strong understanding of this fish if you want one for yourself. That’s where this guide comes in.

Below you’ll learn everything there is to know about Chili Rasbora care. We cover water conditions, size, tank mates, diet, and anything else you’ll need!

Species Summary

The Chili Rasbora (Boraras brigittae), also known as the Mosquito Rasbora, is a tiny schooling freshwater fish that has become quite popular in the aquarist community. Thanks to their vibrant color, Chili Rasboras offer a colorful addition to tanks of all sizes.

Technically speaking, Chili Rasboras aren’t part of the Rasbora family at all! When they were originally found in slow-moving ponds and streams throughout Southeast Borneo, they were classified as a type of rasbora. Since then, scientists have put them in the appropriate genus. But that hasn’t stopped their trade name from sticking.

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No matter what you choose to call them, these fish offer up a unique challenge to fish enthusiasts. They’re not particularly difficult to take care of. However, they do have some strict care requirements if you want them to reach their full potential.


The average Chili Rasbora lifespan is somewhere between 4 and 8 years. While this is shorter than some of the larger fish in the aquarium trade, it’s still a solid amount of time.

Lifespan is heavily affected by the quality of care they receive (mainly water conditions and overall stress). To extend the life of your fish as much as possible, providing a healthy environment is of the utmost importance.


Take one look at these fish and it’s not hard to see why they are so beloved in the fishkeeping world. Their most defining feature is their bright coloration. As you might have guessed from their trade name, Boraras brigittae take on a fiery red hue.

Their entire bodies are covered in shades of red and pink. The red coloration is most vibrant on a horizontal stripe that runs the length of the body. Generally, males tend to have a more vibrant shade of red than females.

Side profile of the Boraras brigittae

The cool thing about this red stripe is that it’s accompanied by a thick band of black. The red stripe is located right on top of the black one, creating a striking contrast that sticks out.

Male specimens also have bright red spots throughout the fins. You can often see them on the dorsal, anal, and tail fin. The fins are all translucent, giving those tiny red spots a floating appearance.

In terms of shape, Chili Rasboras are quite slender. They are girthiest around the midsection, but the body tapers off to the large tail fin. On the heads, the most prominent features are those two large eyes.

The differences between male and female specimens are small but very noticeable. Aside from more color vibrancy for males, female fish tend to be a bit bigger. They’re often a bit rounder and have an overall duller look compared to the males.


The typical Chili Rasbora size is about 0.7 inches long! Since this species doesn’t get very big at all, it’s considered to be a great nano fish and can be found in small tanks all around the world.

Author Note: Some aquarists get concerned when they hear about the size of Chili Rasboras because they think it will be difficult to observe them. Fortunately, thanks to their red color, you won’t have a hard time spotting them in your tank!

Chili Rasbora Care

Chili Rasbora care is considered to be pretty easy no matter how much experience you have. However, you still need to pay attention to water conditions and their environment if you want them to thrive.

Due to the small size of these fish, they have some unique requirements and can easily be affected by stress and poor water quality. Minor changes that are tolerable to larger fish won’t cut it with Chili Rasboras.

Here is some information about Chili Rasbora care that you need to know.

Tank Size

The recommended minimum tank size for Chili Rasboras is only 5 gallons. As you can see, part of the advantage of owning small fish is that you don’t need a ginormous tank to see success. 

With that said, we recommend going with a larger tank if possible. These fish do best in large groups, so you’ll need to increase the amount of tank space to accommodate this.

Regardless of how many you choose to keep, having more room to swim is always preferred. It prevents your fish from feeling cramped and allows you to include more hiding places (which reduces stress).

Water Parameters

The goal when caring for any fish is to recreate their natural habitat in your own aquarium. As we mentioned earlier, Chili Rasboras are found in Borneo. They occupy small ponds and very slow-moving streams.

Most of the bodies of water they are found in contain blackwater. Basically, this water is stained brown because of organic chemicals released by dying leaves at the bottom. As a result, the water is a bit on the acidic side.

Don’t make the mistake of thinking that blackwater is dirty water. It’s actually quite clean and doesn’t contain many minerals like other types of water. Chili Rasboras do not tolerate a ton of nutrients, pathogens, or waste. We’ll get into adjusting water quality in a bit.

Here are the main parameters to know:

  • Water temperature: 68°F to 82°F (aim for 74°F if possible)
  • pH levels: 4.0 to 7.0 (6.0 is ideal)
  • Water hardness: 3 to 12 dKH

Author Note: Since these fish can be sensitive to shifts in water conditions, it’s important to monitor these levels consistently. We recommend picking up an accurate water testing kit (even if it costs more) just to make sure you know the state of the water in your aquarium.

What To Include In The Tank

Creating the perfect environment is key to keeping your fish healthy. Not only does your tank decor affect safety and overall happiness, but what you decide to introduce into the tank can affect water quality as well.

Let’s start with the water itself.

Earlier, we mentioned that natural blackwater ponds are pretty low in minerals. Well, this could be a problem when you’re using tap water.

You see, tap water typically contains chlorine, trace amounts of copper and a slew of other chemicals. These minerals could affect the health of Chili Rasbora. To make matters worse, filtration methods could introduce high levels of sodium into the mix!

To overcome these issues, we recommend filling your tank with distilled water. Distilled water is very soft and doesn’t have the high mineral content of tap water. If you do use tap water, make sure that you invest in a water conditioning solution.

This simple water treatment will get rid of those unnecessary minerals and chemicals, preparing the water for your fish.

Now for the rest of the tank.

At the bottom of the tank, use a dark substrate. You can use fine gravel or even sand. This mimics the leave-covered floors of blackwater ponds.

You can then add a bunch of driftwood and floating plants. Java fern, Anubias, and Java moss are all great options. Boraras brigittae love plants and will often spend their time swimming through the leaves.

A group of Chili Rasboras swimming together

It’s also recommended that you add some peat moss or peat pellets. These additions to the tank will decompose over time. While it might seem counterproductive, it’s actually very beneficial to Chili Rasboras!

As the moss decomposes, it will provide a light tint to the water. This is caused by tannins being released. Tannins are an organic chemical compound that’s believed to help bring out the color vibrancy of Chili Rasboras.

Not only that, but the tannins can help reduce the overall pathogen levels in the water. That slight tint may make the water look dirty, but it’s anything but! Adding moss recreates that blackwater look without making the tank dirty.

As for equipment, powerful filtration is key. Smaller tanks can get away with a simple hang-on-back filter. However, larger aquariums may need a powerful canister filter (we recommend the Fluval FX4).

Whatever the case may be, you need to make sure that the outlet flow is as low as possible. Chili Rasboras aren’t strong enough to swim against strong currents. They need slow-flowing water to stay happy, so avoid strong pumps. The addition of plants and driftwood can also help to break up any existing flow from your filters.

Diseases To Watch Out For

We’re happy to say that Chili Rasboras aren’t affected by any diseases that are exclusive to the species. The only issues you need to worry about are those that affect freshwater fish as a whole. This includes parasitic infections, fungal problems, and more.

The most common ailment to affect freshwater fish is Ich. It’s an external parasite that causes white dots to appear all over the fish’s body. In most cases, Ich is caused by stress. You can avoid it by maintaining water conditions and providing your fish with a very healthy diet.

Ich is pretty contagious, so you need to keep an eye out for it and separate infected fish as quickly as possible. Luckily, there are many over-the-counter medications you can use to bring your fish to good health.

Author Note: The most important thing you can do if you want to keep your fish happy and healthy is keep the water quality in great shape and feed them good food. Most diseases come as a result of these, and prevention is always easier than treatment.

Food & Diet Recommendations

Chili Rasboras are considered micro predators. In the wild, they feed on microscopic sources of protein like plankton, worms, insects, and more.

In captivity, these fish will eat pretty much anything you give them. They do quite well on a balanced diet of fish flakes or small pellets.

However, they do love protein as well. Feel free to provide baby brine shrimp, Tubifex, micro worms, and Daphnia every once in a while to supplement dried food.

Temperament & General Behavior

Chili Rasboras are very peaceful fish and can actually be a bit timid at times. However, they will start exploring the tank more once they feel comfortable.

Typically, Chili Rasboras will stick to the upper half of the aquarium. They may venture down to the bottom of the tank on occasion, but that’s less common. It’s not unusual to find these fish exploring hiding spots or swimming through vegetation.

If you have more than one Boraras brigittae in the tank, they will group up. These are schooling fish that thrive in large groups. They will swim together, creating swaths of beautiful color throughout!

Tank Mates

Just because they are small doesn’t mean that they do well with all fish. Remember, these fish don’t even make it past an inch in size! The biggest issue you’ll have to deal with is other fish thinking that your Chili Rasboras are food!

If you do want to make a community tank, stick with similarly sized fish that are just as passive as Chili Rasboras. Here are some good tank mates to consider:

Author Note: A lot of aquarists also wonder if these fish can be kept with Cherry Shrimp, and the answer is yes. 

Chili Rasbora Breeding

Breeding Chili Rasboras is easy. In fact, it’s a little too easy. These fish are continuous spawners. This means that they will lay eggs regularly if conditions are good.

It’s recommended that you create a separate breeding tank for Chili Rasboras if you want to protect the spawn. Unlike other fish, Mosquito Rasboras are not parental at all. They may attack or eat the fry.

A lot of vegetation towards the bottom of the tank is ideal. You can also invest in faux grass.

When a female is ready to lay eggs, she’ll scatter them throughout the bottom of the tank. At this point, you need to remove the fish from the tank to give the eggs a chance to hatch.

It won’t take long for the fry to emerge. In most cases, they hatch in a couple of days. For the first 24 hours, the fish will feed on the egg sac. Then, they’ll consume microscopic food like Infusoria.

After about 10 days, you can switch to micro worms.

Want One For Yourself?

Now you know the essentials when it comes to Chili Rasboras and how to care for them. These tiny little critters are a breeze to care for and a ton of fun to watch swim around your tank.

Their size also gives you the flexibility to keep them in a nano tank. This is great for individuals without a lot of space or looking for something small to include in their room.

We’ve been huge fans of this species for quite a while, and find ourselves recommending them to other aquarists all the time. We hope this guide encouraged you to give the Chili Rasbora a shot!

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