Chili Rasbora With Betta

Chili Rasbora With Betta

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Betta fish are known to be territorial and aggressive, which is why these beautiful fish are also known as Siamese Fighting Fish! However, many bettas can also get lonely if kept alone, and they benefit from the company of a few suitable tank mates.

Generally, small, peaceful fish make the best companions for bettas, and invertebrates, such as snails and shrimp, also work well. 

So, are Chili rasboras a good fit for bettas? 

Keep reading to find out!

What Are Chili Rasboras?

Chili rasboras, the scientific name Boraras brigittae, are sometimes also called Mosquito rasboras.

This tiny schooling freshwater fish only measures ½ an inch or so in length at maturity, so they are just about the smallest fish you can buy for your fish tank. Brightly colored and active, these shoaling fish are easy to care for, although they can be sensitive to shifts in water conditions and quality. For that reason, these fish aren’t the best choice for a beginner fish keeper.

Chili Rasbora vs. Betta

So, how do Chili rasboras stack up when compared directly with bettas?

Origins and Natural Habitat

Bettas are native to Asia. The fish live in slow-moving bodies of water, including rice paddies, marshland, small streams, and ponds.

Chili rasboras come from southwestern Borneo and parts of Indonesia, specifically the provinces of Kalimantan Selatan and Kalimantan Tengah. Like bettas, these little fish inhabit slow-moving pools and streams, although the water here is “blackwater” that’s very low in minerals and salts.

Both species live in heavily vegetated habitats where the light is relatively dim.


Chili rasboras are tiny, bright red fish that create a wonderful display when kept in a large school. Bettas are also very colorful fish that have extravagant finnage, depending on the variety.

Betta fish can reach up to 3 inches in size when fully grown, whereas the Chili rasbora only measures 0.8 inches in size.

Life Expectancy

Despite their minuscule size, the rasboras can survive for up to eight years when given the correct care. Bettas generally have a lifespan of between two and five years.

Behavior and Temperament

Male betta fish are famous for their feisty temperament and tendency to be aggressive. These are territorial fish that cannot be kept together. However, bettas enjoy the company of peaceful species. Bettas spend much of their day patrolling the tank and resting on flat leaves or in caves.

Chili rasboras are lively little creatures that enjoy schooling in the midwater area. Since bettas tend to gravitate to the upper area of the water column, the two species won’t clash in your tank.  Rasboras are peaceful and somewhat timid, needing to live in groups of at least five individuals to be happy.

Rasboras are not known to be fin nippers, which is essential if they are kept with a betta fish. However, Chili rasboras are shy and easily spooked, and a curious betta could be a problem for these little fish. Also, bettas have been known to make a meal out of a very small rasbora!

Diet And Feeding

Both betta fish and Chili rasboras are omnivores, although bettas are primarily meat-eaters. However, essentially, you can feed both species pretty much the same balanced diet of fish flakes and high-quality mini pellets, supplemented with frozen meaty foods, such as bloodworms, daphnia, and mosquito larvae.

You can feed betta fish and Chili rasboras twice daily. However, bettas benefit from one fasting day each week. That’s because bettas can suffer from health conditions, such as bloat, swim bladder problems, and constipation, and a food-free day helps to prevent that.

Tank Requirements

Tank Size

Both bettas and Chili rasboras are generally regarded as nano fish. So, you can keep both species in a minimum tank size of 5-gallons, although a larger aquarium is recommended if you’re keeping a community fish setup.

A long tank works best for both species. Why? Well, bettas aren’t the strongest swimmers, and they need to be able to get to the surface with minimal effort to feed and breathe air through their labyrinth organ. Chili rasboras are a shoaling species that require plenty of open water swimming space.

Bettas and rasboras can both jump, so your tank must have a tightly fitting lid!

Tank Decoration

All fish species do best when kept in a tank that mimics their natural habitat.

Bettas and rasboras have similar requirements in that they both enjoy a well-planted tank with plenty of hiding places. Open swimming space is also essential. In the wild, Chili rasboras live in blackwater habitats where the substrate is usually sand or fine gravel, usually with a layer of leaf litter across it. Although bettas can benefit from adding dried almond leaves to their tank, these fish are not blackwater species.

You can also include plenty of driftwood, rockwork, twisted roots, caves, and overhangs so that the fish have somewhere to hide if they want to.

Habitat Requirements


Both bettas and Chili rasboras live in slow-moving or even stagnant waters with virtually no current. So, in your tank, you need a filtration system that doesn’t generate too much flow, or both these fish species will struggle to swim. With that in mind, a sponge filter is perfect for betta fish and rasboras. 

Water Parameters

So, Chili rasboras need a particular set of water parameters if they are to thrive. But do those parameters suit the betta fish, too?

Water Temperature

Chili rasboras need a water temperature of between 68° to 83° Fahrenheit. Betta fish need warm water at a temperature between 75° and 81° Fahrenheit. So, that’s comparable.

Note that, for bettas, the ambient room temperature should be as close to that of the tank water as possible so that the betta’s labyrinth organ isn’t damaged.

Water Hardness and pH

Chili rasboras need very soft water with a pH range of between 4.0 and 7.0 and a water hardness of between 1 and 10 dKH. Bettas need a pH range of 6.5 to 7.5 and a water hardness of between 3 and 5 dKH, so the two species can tolerate very similar water conditions. Spend the extra money on an accurate water testing kit to ensure these results.


Bettas and Chili rasboras live in relatively dark waters in the wild, primarily due to overhanging trees and dense aquatic vegetation. You can mimic that in the aquarium by using floating plants or investing in a lighting unit that you can adjust to keep the lighting low.

Tank Maintenance

Bettas can be very sensitive to poor water conditions, so you’ll need to keep your tank well-maintained and clean. Although rasboras tend to be less fussy, you should keep the aquarium in good order to prevent your fish from becoming stressed. 

Both species appreciate well-oxygenated water. Bettas cannot derive all the oxygen they need from the water, so they must visit the water surface periodically to breathe atmospheric air through their labyrinth organ

For both Chili rasboras and bettas, the water parameters must remain constant and stable. Any rapid fluctuations in temperature or water conditions can cause mass fish kills in rasboras and will also make your betta sick.

Clean The Tank

Use an aquarium vacuum cleaner every week to suck out any organic waste matter from the substrate. Focus on areas under decorations, around plant stems, and underneath your internal filter. Be sure to work right down into the gravel or sand to break up any dead zones where harmful toxins might accumulate. 

If you neglect that task, the waste will decompose, releasing ammonia in the water, placing extra load on your biological filter, and potentially resulting in an ammonia spike that could kill your fish. Remember, ammonia and nitrite levels must be zero.

Also, trim off any brown or dead plant stems and leaves, and remove overgrowth.

Partial Water Changes

While cleaning the aquarium, change 20% of the water to ensure that nitrates are kept to a minimum. Ideally, nitrate levels should be below 20ppm.

Filter Maintenance

So, once a month or so, you need to wash the filter media in dirty water from the tank to prevent the sponges from getting clogged with solid waste particles. Also, rinse the area around the impeller to make sure it’s not obstructed and can spin freely. 

You’ll also need to replace spent filter media periodically in line with the individual manufacturer’s guidelines. Neither bettas nor Chili rasboras are foul fish, so your filter media should last, provided you keep it well maintained and don’t overcrowd the tank.

Health and Disease 

Both betta fish and Chili rasboras are pretty hardy fish, provided the water parameters remain stable. However, there are a few health conditions you should be aware of that could affect both species.

White Spot Disease(Ich)

White Spot disease is also commonly called Ich or Ick. 

This condition affects virtually every freshwater fish species and is probably the most common ailment that hobbyists encounter. There’s also a marine version of White Spot Disease.

White Spot disease is caused by a common aquatic parasite called Ichthyophthirius multifiliis. The parasite is found in most fish tanks, only causing problems when fish are weakened by stress or some other kind of disease.

Fish with Ich usually flash or flick against the substrate and solid objects in the tank in response to the irritation the parasites cause. After a few days, the fish develop a rash of tiny white spots across their body, gill covers, and fins.

Luckily, Ich is easily treatable by raising the water temperature to 82 degrees Fahrenheit and treating the tank with a White Spot medication.


Fungal infections are also widespread and are usually the result of poor water quality and a dirty tank. 

The infected fish develop white, cotton-like growths on their body, around the mouth, and on the head. To treat the condition, dose the water with antifungal treatment, give the tank a thorough cleaning, and pay attention to your aquarium maintenance regime!

Bacterial Infections

Bacterial infections can manifest themselves in different ways. Some bacteria attack the fish’s body, while others affect the gills or fins, and some destroy the fish’s internal organs.

There are lots of symptoms associated with bacterial infections, including:

  • General malaise
  • Lethargy
  • Loss of appetite
  • Red patches on the skin
  • Torn fins

Generally, if you feed your fish a high-quality diet, don’t overfeed them, avoid overcrowding, and keep the aquarium clean and with stable water conditions, outbreaks of disease are rare.


You can breed bettas and Chili rasboras relatively easily in your home tank.

Both species are egg layers, but that’s where the similarity ends. 

Chili Rasboras

These small-sized fish readily breed if given a good diet and plenty of planting where the eggs and fry can be safe from other fish, including your betta. 

You’re almost guaranteed to have a mix of female and male fish in any given school size. Once the fish are mature, around six months of age, spawning happens almost continually. The eggs drift to the bottom of the aquarium, usually hatching within 36 to 72 hours. In a further 36 to 48 hours, the fry are free-swimming.

Other fish in the tank that view the babies as a food source pose the biggest threat to the fry. That said, if you have provided plenty of hiding places, there’s a good chance that some of the fry will make it.

Betta Fish

Bettas are also very easy to breed in the home aquarium. 

Male bettas build bubble nests, usually underneath floating plants, flat leaves, or in a corner of the tank. The male betta courts the female fish until spawning takes place. The eggs are released, dropping to the substrate underneath the nest. The male then picks up the eggs and transfers them, one by one, into the nest. He then stands guard until the eggs hatch.

The fry feed off their egg sacs for a few days until they become free-swimming.


You can buy Chili rasboras and betta fish in most fish stores and online. Rasboras usually cost a few dollars per fish, whereas bettas retail at upwards of $15, depending on the colors and finnage of the fish.

So, Can These Species Live Together?

What’s the verdict?

In Summary

In theory, there’s no reason why Chili rasboras and betta fish can’t be tank mates.

The two species share similar temperature and water parameter requirements, and they both like a well-planted tank with plenty of hiding places. Since both bettas and rasboras are small fish, you can keep them in a 5-gallon nano tank. Also, both species enjoy a similar diet.

However, there are a couple of potential issues with keeping Chili rasboras and betta fish together:

  • Bettas are aggressive, territorial fish that can potentially stress the shy rasboras.
  • Bettas are considerably larger than Chili rasboras and could view them as a potential food source.

That said, every betta is an individual, and some are more peaceable than others. Also, if you keep a large school of rasboras in a larger fish tank, it’s much less likely that confrontations will occur. Also, be sure to provide plenty of hiding places and heavy planting so that the tiny rasboras have somewhere to get away from the betta if they want to.

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