Species description

Care, breeding and tankmates

Fish profile

Temperament

Peaceful

Chili Rasboras are extremely peaceful, docile, and somewhat shy fish that will not bother any tankmates. They are schooling fish that derive their confidence from being in a group, exhibiting schooling behavior when kept in sufficient numbers. During the breeding period, males may display minor, non-aggressive territorial behaviors towards rivals, which consist of harmless fin-flaring. Because of their tiny size and timid nature, they can easily become intimidated by larger or more active species.

Diet

Micro-predator

In their natural habitat, Boraras brigittae are micro-predators feeding on zooplankton, small insects, and micro-crustaceans. In the aquarium, they should be offered small-sized foods suitable for their tiny mouths, such as crushed high-quality flakes or micropellets. Regular feedings of live or frozen foods, such as baby brine shrimp, daphnia, cyclops, and vinegar eels, are highly recommended to bring out their best coloration and health. Biofilm growing on leaf litter and plants also provides a natural source of supplemental nutrition.

Life expectancy

4-8 years

In captivity, Boraras brigittae can live for 4 to 8 years when provided with optimal, stable water parameters and a high-quality diet. Their lifespan is significantly influenced by the consistency of their environment, as they do not tolerate sudden shifts in temperature or pH. Feeding a varied diet consisting of live and frozen foods alongside dry staples will also contribute to their longevity. Proper husbandry, including routine maintenance and stress reduction, is essential for helping them reach their maximum lifespan.

Sex ratio

Group

These fish are highly social schooling animals and should always be kept in groups of at least 8 to 10 individuals, though 15 or more is highly recommended. There is no strict sex ratio required, but keeping a mixed group with multiple males will encourage them to display their most vibrant spawning colors. In larger groups, males will engage in harmless, beautiful territorial displays without causing any physical injury. Providing a natural group structure helps reduce shyness and ensures the fish feel secure in their environment.

Feeding frequency

Twice daily

Because of their high metabolism and very small stomachs, Chili Rasboras benefit from being fed small amounts two to three times a day. Each feeding should consist of only what they can consume within a minute or two to prevent excess food from decaying and spoiling the water. Overfeeding can quickly lead to water quality issues, which these sensitive fish do not tolerate well. A consistent feeding schedule helps maintain their energy levels and supports their vibrant colors.

Bioload

Low

Boraras brigittae is an exceptionally small species, reaching a maximum size of just under an inch, resulting in a very low bioload. Despite their minimal waste production, they are sensitive to fluctuations in water chemistry, requiring stable conditions to thrive. A well-established tank with a gentle sponge filter or a low-flow hang-on-back filter is ideal for maintaining pristine water quality without creating disruptive currents. Regular small water changes are recommended to keep nitrates at a minimum while avoiding sudden parameter shifts.

Flow

Stagnant

This species naturally inhabits slow-moving streams and peat swamps, meaning they have a strong preference for weak water flow. Strong currents should be strictly avoided, as they will quickly exhaust these tiny fish and may push them around the tank. Air-powered sponge filters or filters with adjustable flow rates are highly recommended to provide gentle filtration. Creating quiet zones with dense planting and driftwood will allow them to rest comfortably without fighting the current.

Jump risk

Yes

Due to their active nature and tendency to startle easily, Chili Rasboras are considered a moderate jump risk. They may leap from the water if they are chased, spooked by sudden light changes, or stressed by poor water quality. A tight-fitting lid or cover slides are highly recommended to prevent accidental escapes from the tank. Incorporating floating plants can also help create a natural barrier and make the fish feel secure enough that they are less prone to jumping.

Reproduction

Oviparous

Breeding Boraras brigittae is moderately difficult but highly rewarding, as they are egg-scatterers with no parental care. To encourage spawning, a dedicated breeding tank with soft, acidic water (pH 5.0-6.5) and plenty of fine-leaved plants like Java moss is necessary. The parents should be conditioned with high-protein live foods and then removed after spawning to prevent them from eating the eggs. The tiny fry hatch in about 24 to 36 hours and must be fed microscopic foods like infusoria or paramecium before graduating to baby brine shrimp.

Compatibility & tankmates

Species only

Due to their miniature size, Chili Rasboras are only compatible with other small, peaceful, and non-aggressive species. Suitable tankmates include small danios, dwarf corydoras, kuhli loaches, and other peaceful nano fish. They are also excellent companions for ornamental shrimp, such as Cherry and Crystal shrimp, as they are too small to prey on adult shrimp or even larger juveniles. They must never be housed with larger or boisterous fish that could view them as a food source or stress them with active behavior.

Tank level

Top/Middle

Chili Rasboras primarily occupy the middle and upper levels of the water column, where they actively swim and explore. They prefer tanks with dense vegetation, floating plants, and driftwood, which provide shelter and shade in these upper zones. When feeling secure, they will occasionally venture to the bottom of the tank to forage for food along the substrate. Keeping them in larger schools encourages them to swim more freely in open water rather than hiding in the plants.