Chili Rasbora (Boraras Brigittae): Care Guide & Species Profile

Mosquito Rasbora (Boraras brigittae) Beautiful Endemic Ornamental fish from Borneo
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: February 28, 2024
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If you are searching for a new inhabitant for your nano tank, designing a paludarium, or just wishing to introduce some hues, the chili rasbora makes an excellent choice for your freshwater aquarium. We were inspired to create this care guide due to the captivating, vibrant red coloration and spirited nature of the chili rasbora. Continue reading to discover the fundamental care necessities, how to arrange your tank before the arrival of your fish, and the measures to take if it falls ill.

Article Summary

  • The chili rasbora is a small fish with bright red coloration and a black and red line along its body, as well as translucent fins with occasional red spots.
  • For an optimal Chili rasbora tank setup, use a dark substrate such as fine gravel or sand to replicate the natural habitat, and ensure the inclusion of a necessary filter, preferably with a low outflow.
  • These rasboras are prone to common freshwater fish diseases, including gill flukes, fin rot, and swim bladder disease.

Species Overview

Common namesChili Rasbora, Mosquito Rasbora
Scientific nameBoraras brigittae
SpeciesB. brigittae
Size1 in
Lifespan4-8 yrs
FamilyCyprindae
GenusBoraras
DistributionIndonesia
ColorRed
DietOmnivores
TemperamentPeaceful
Minimum tank size10 gallons
Place in the tankTop half
Care LevelBeginner
Breeding Easy

History and Background

Chili rasboras are hardy fish that were first described by Dieter Vogt in 1978. In their natural habitat, they can be found hanging out in the pools and streams of Indonesia. Learn more below about these fantastic fish, where they came from, and what it means for your aquarium.

What chili rasboras?

One of the smallest tropical fish, the chili rasbora (Boraras brigittae) are peaceful fish that are popular in nano tanks because of their small size and spicy personality. Also called mosquito rasboras, this fish is a schooling fish that is quite popular in the aquarium trade.

Where did the chili rasbora come from?

These fish are native to Asia, more specifically Indonesia in the southern parts of Borneo. Their natural habitat includes freshwater swamps and blackwater pools and streams. In other words, they prefer slow moving flow with acidic water. You will often find them in the leaf litter of their water source looking for insect larvae as part of their carnivorous diet.

FUN FACT

The mosquito rasbora isn’t actually a rasbora! Although originally described as rasbora urophthalma brigittae,the species was later reclassified as boraras brigaittae. Despite this, the common name, rasbora, has stuck and the aquarium trade still calls them by it to this day.

Chili rasbora Appearance

closeup image of a chili rasbora, also known as mosquito rasbora
(1) Closeup Image of a Chili Rasbora

For the Boraras brigittae, their appearance is definitely what’s started their popularity in the aquarium trade. If you’re looking for a tiny fish that will pack a punch with bold, contrasting colors, then look no further than the chili rasbora.

What do chili rasbora look like?

These fish tend to light up the aquarium with their bright red coloration. Other body features include a black and red line that runs laterally along the length of their body giving bold contrast to their coloration. The fins of this fish are mostly translucent, though they will occasionally have red spots. The fish is long and slender and has a large caudal fin. Additionally, they have two very large eyes.

How to sex the chili rasbora?

The differences between male and female fish includes the male fish being more vibrantly colored and the female being slightly rounder. Additionally, the male will have red highlights along their dorsal and anal fins which are not present on the female. While these differences sound subtle they are very noticeable when the two species are placed side by side.

How big does a chili rasbora get?

This fish grows to the maximum size of one inch. This means it’s an excellent choice for a nano tank or community tank with other tiny fish.

How fast do chili rasbora grow?

Since they are such a small size this fish grows fairly rapidly. You can expect it to reach full size by the time it is one year old.

Temperament and Tankmates

A red fish swimming in a planted aquarium
(2) Chili Rasbora Swimming In A Planted Aquarium

As a pretty social fish, chili rasboras do best when kept in groups. They tend to get along with other aquarium species and are generally considered non-aggressive. When choosing tank mates, your biggest concern will be ensuring your chili rasboras don’t end up a snack for another fish!

How many Chili Rasbora should be kept together?

As schooling fish you should expect to keep at least 6 of these tiny fish together. However, the larger the school the more this small fish thrives so it is recommended to increase school size to roughly 20 fish.

If you are planning on increasing the school size of this freshwater fish, you should expect to increase the size of the aquarium. While 20 gallons is enough room for 6 fish, we recommend a tank of 35 to 40 gallons for a school of 20.

What fish can live with chili rasbora?

The most important thing when considering whether a tank mate would be a good companion or not is what size the other fish are. While the chili rasbora is a very peaceful fish and could get along with most larger fish temperament wise just fine, they will likely be mistaken as a snack when placed with larger fish.

Top 5 tank mates

  1. Neon tetra– of course this nano fish would make the top of our list for good tank mates. The neon tetra will get along great with chili rasboras in a small aquarium and has similar tank requirements.
  2. Cory Catfish-including various species like the Ehrhardti cory, are known for their preference to inhabit the middle and bottom levels of your tank, creating a dynamic contrast to the mosquito rasbora, which tends to favor the top levels.
  3. Cherry Shrimp-if you’re looking for another member of the tank cleanup crew consider adding some adult shrimp to your tank.
  4. Neon Green rasboras-If you’re looking for another small tank superstar to compliment red coloration this fish will provide beautiful contrast.
  5. Cherry Barbs-Though cherry barbs have the same coloring as chili rasboras and are sometimes mistaken for the same species, these two freshwater fish get along well.

Other fish that would make excellent tank mates for your nano tank include the cardinal sulawesi shrimp, zebra danios, sixray corydoras, or the sparkling, opaline, or blue gourami.

Tank mates to avoid

In short, any fish that requires a larger tank, or aggressive nano fish will not work well with chili rasboras. Additionally, nano fish that are not able to adjust to warm temperatures of slightly acidic water are not compatible. Listed below are 5 species you should definitely not pair with this species.

  1. Goldfish– This much bigger, omnivorous fish is apt to make a meal out of your chili rasboras.
  2. African Cichlids– Well known in the aquarium trade for their aggression, african cichlids won’t pair well with your peaceful chili rasboras.
  3. Oscars– Aggressive and territorial, this is another freshwater fish you’ll want to avoid pairing with chili rasboras.
  4. Betta– Known to attack even members of its own species, chili rasboras and bettas won’t do well together.
  5. Angelfish– These fish greatly outweigh chili rasboras in terms of size which could cause issues.

Tank Requirements

A Planted Aquarium
A Planted Aquarium

Tank conditions are vital for chili rasbora care, and incorporating self-cleaning tanks promotes a healthier environment by maintaining optimal water quality and reducing waste accumulation.

For this species, slow moving water that doesn’t fluctuate greatly in temperature, pH, and water hardness is a must. Sudden changes in tank conditions are very likely to negatively impact this fish.

Water Parameters

Tank Size>20 gallons
Water TypeFreshwater
Water Temperature70-76
Water pH4-7 (6.0 ideal)
Water Hardness3-12 dKH

TIP

Because of their sensitivity we recommend only using distilled water in your aquarium instead of tap water in order to provide the best chili rasbora care.

Tank setup:

What substrate should I use?

Add dark substrate (fine gravel or sand) that is appropriate for your tank size. This will represent the leaf covered bottom of the chili rasboras natural habitat. As an added bonus it will also contrast against your chili rasboras bright coloration.

Is a filter necessary?

It is absolutely necessary to have a filter in your own aquarium. While they are generally hardy fish, chili rasboras are extremely sensitive to poor water quality. Most nano tanks can use a sponge filter that hangs on the back of the main tank. However, be sure that the filter you choose is set to the lowest outflow possible. Chili rasboras aren’t strong fish and a strong water flow will prevent them from swimming throughout the water column and likely stress them out.

TIP

You should never use untreated tap water in your aquarium. Tap water that is not treated can contain chlorine and other chemicals that can be harmful for your fish.

Do I need to purchase a pump?

We recommend not using a pump in your fish’s tank. Chili rasboras are sensitive to water flow and in small tanks the filter will usually provide enough circulation throughout the water column.

Should I have a water heater?

You will need a water heater for your tank to maintain the proper temperature range for your fish. As tropical fish (and nano fish!), they are very sensitive to changing water parameters and will not tolerate an aquarium that is too warm or cold.

What kind of lighting to use?

We recommend having dim lighting for your chili rasboras. This is mostly because they are used to the black, tannin stained water of their natural environment. If other fish in your tank need a brighter light you can provide a dimmed area using plant cover.

Should I add plants to my tank?

Creating a paludarium is an excellent way to provide entertainment and engagement for these fish in a planted aquarium. By incorporating elements such as peat moss, driftwood, and other aquatic plants, you not only enrich their environment but also improve their water parameters.

TIP

Adding peat moss or pellets to your water will add natural tannins to your water. Tannins are an organic chemical compound that not only will lower pathogen levels but increase the vibrancy of your chili rasboras. Many people think the tint that tannins give the water is a sign of a dirty tank but it’s actually very healthy and part of excellent chili rasbora care!

Do chili rasboras need a heater?

Yes, we strongly recommend the addition of a water heater to your tank to help maintain water temperature. If you are having trouble choosing one we have several guides available on our website.

Do rasboras like fast flowing water?

No, having high flowing water is the fastest and easiest way to stress your chili rasboras out. If your filter has a high flow try adjusting it by placing a sponge underneath the output.

Do rasboras need live plants?

While rasboras do prefer live plants, these might be difficult for you to keep due to low lighting requirements and more acidic conditions. We recommend using floating plants- such as java moss- as an alternative to rooted live plants. This will allow your rasbora the benefits of live plants while being easier for you to maintain. Additionally, you can have full lighting above your tanks which allows your plants to grow, but the floating plants will shield your fish from the full light effect.

Diet and Health

Fish Food
Different Type of Food for Fish

While this fish is not particularly picky when it comes to food, providing a balanced diet can be tricky because of their small mouth size. When planning their diet remember that high quality food is more important than giving them a high quantity of food.

What do chili rasbora eat

In the wild, chili rasboras are considered micro predators and eat a diet consisting of mainly meaty foods. This can include mosquito larvae, insects, and fish fry.

What to feed chili rasbora?

Feed your chili rasboras a varied diet that is representative of the one they would eat in the wild. Live or frozen foods that are rich in protein such as micro worms, baby brine shrimp, and daphnia should make up roughly 20% of the fish diet. The remaining 80% should consist of fish flakes specifically designed for chili rasbora (Boraras brigittae) to enhance their coloring and ensure they are receiving the vitamins and minerals they need.

TIP

Because they are so small, it is necessary to feed baby shrimp instead of full size shrimp.

How often to feed chili rasbora?

Feed your chili rasboras once daily. If you are feeding them with slightly larger fish be sure that they get their own small food and are not outcompeted.

How much to feed chili rasbora?

Feed your chili rasboras in accordance with the three minute rule. This will ensure that they are getting enough nutrition without overeating. When feeding, pay attention to all of your fish to ensure that they are all eating and not being pushed aside by others.

Common diseases of chili rasbora?

There are no species-specific diseases known for chili rasboras, however, like all freshwater fish they can be susceptible to freshwater fish diseases such as parasites, fungal infections, swim bladder disease and more.

  • Gill Flukes– a common parasite in freshwater fish, gill flukes attach onto the gills of the fish and look like a small white or gray spot. Other symptoms include trouble breathing and lack of energy. Proper treatment includes an antiparasitic, it is recommended to find one containing Praziquantel for best results. Gill flukes are often a result of a fish’s immune system being depleted from bacterial or fungal infections and not being able to fight off the parasite. Before treating with an antiparasitic be sure to treat the initial bacterial or fungal infection.
  • Fin Rot– Often caused by an injury in addition to poor water quality, if left untreated fin rot can cause your fish’s whole fin or tail to fall off. Symptoms include the fins and tail having a ragged appearance and continually degrading. Treatment includes a broad spectrum antibiotic, and aquarium salts. You will potentially have to treat your fish for a secondary fungal infection.
  • Swim Bladder Disease-If you notice your fish is having a hard time swimming, is leaning to one side, or is unable to remain upright then it is likely that they have swim bladder disease. Treatment options include water changes, lowering the water level so that they are upright, epsom salt baths, and potential treatment using antibiotics if the case is severe.

How long do chili rasbora goldfish live?

This fish lives 4 to 8 years in the ideal conditions and with proper chili rasbora care.

Breeding

Mosquito Rasbora In An Aquarium
(3) Mosquito Rasbora In An Aquarium

Some of the easiest fish to breed, chili rasboras, are low maintenance when it comes to breeding. Not only do the fry take a short time to hatch, but you also don’t have to induce mating in this species.

Can you breed a chili rasbora?

This fish is one of the easiest to breed as they are continuous spawners. Most aquarists have a harder time preventing them from breeding than they do initiating spawning.

How to breed a chili rasbora?

If you are planning on breeding your own chili rasboras it is recommended to create a separate breeding tank as these fish are liable to eat their own eggs. As continuous spawners you won’t have to induce mating in the fish, they will do it on their own. If you are watching closely you might see the fish performing a mating dance which is often interpreted as the male chasing the female and nipping at its fins.

Once the female lays her eggs remove the adults from the breeding tank. The fry will hatch within 48-72 hours. They will feed on the egg sac for the first 24 hours after hatching and then become free swimming. Baby chili rasbora care includes feeding them microscopic foods such as infusoria for the first two weeks before transferring to larger food such as micro worms.

Because they are not aggressive and do well in schools it is not necessary to separate the fry into different breeding tanks as long as your original one is the minimum tank size for the amount of adult fish (20 gallons per 6 fish).

Chili rasbora FAQS

What age do chili rasbora become red?

They will reach their full vibrant coloration when they reach sexual maturity (4-6 months) but you will likely notice their coloration beginning to appear long before that.

TIP

Chili rasboras coloration can be affected by their stress. Examples when their coloration would not be as bright includes recently moving tanks, high flowing water, and bad tank mates.

Can I put chili rasboras with a betta? 

No, these two fish would not make good tank mates, and the betta would likely end up eating the chili rasboras. It’s not even a good idea to put them in separate tanks close to each other as your betta might mistake the bright red coloration of the chili rasbora as a challenging male.

Can you keep rasboras with shrimp? 

Yes, chili rasboras and shrimp actually do quite well together as they are both peaceful species.

Are chili rasboras fin nippers?

No, there are only two times you might notice your chili rasboras nipping fins. One, when the male is courting the female as part of the mating ritual and two, when first introduced to their school to establish hierarchy.

Is the chili rasbora for you?

Whether you’re interested in its coloration or curious about how it lives in blackwater environments, chili rasboras can be a worthy investment for aquarists who are considering small fish.

Conclusion

When purchasing chili rasboras you should be prepared to maintain pristine water conditions, provide a rich diet, and plenty of friends. You should also expect to have hours of entertainment, spicy personalities, and a great addition to your aquarium.

(1) JoKrimmel, CC BY-SA 4.0, via Wikimedia Commons
(2) Atulbhats, CC BY-SA 4.0, via Wikimedia Commons
(3) Atulbhats, CC BY-SA 4.0, via Wikimedia Commons

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