Species description

Care, breeding and tankmates

Fish profile

Temperament

Territorial

This is an extremely peaceful, timid, and schooling species that only feels secure when kept in large numbers. Males may display mild and temporary territoriality during spawning periods, engaging in harmless sparring displays to impress females. Their reserved nature makes them unsuitable for tanks with large or boisterous fish, which can easily intimidate them and force them into hiding.

Diet

Carnivore

In the wild, *Boraras merah* is a micro-predator feeding on small insects, worms, crustaceans, and other zooplankton in blackwater biotopes. In captivity, they will accept high-quality crushed flakes and micropellets, but they require live and frozen micro-foods to display their best colors and maintain vitality. Foods such as baby brine shrimp, daphnia, microworms, and copepods are ideal and easily consumed by their tiny mouths.

Life expectancy

3-5 years

Under optimal care conditions, this species has a captive lifespan ranging from 3 to 5 years. Reaching their maximum potential age is closely tied to maintaining stable, soft, and acidic water conditions that mimic their natural blackwater habitats. A varied diet rich in high-quality live and frozen foods also plays a crucial role in supporting their long-term health and immune system.

Sex ratio

Group

This species does not require a strict male-to-female ratio and benefits most from being kept in a large group of at least eight to ten individuals. Within the shoal, the presence of multiple males encourages healthy intraspecific competition, prompting them to display their most intense spawning colors and fascinating sparring behaviors. Females, which are typically rounder and slightly less colorful, help balance the group dynamics and reduce overall stress for individual fish.

Feeding frequency

Twice daily

Given their small size and rapid metabolic rate, it is best to feed them small amounts two to three times a day rather than one large feeding. This feeding schedule ensures that all individuals receive adequate nutrition and minimizes uneaten food that could spoil the water. Regular small feedings also mimic their natural foraging behavior of searching for food throughout the day.

Bioload

Low

Due to its exceptionally minuscule size, rarely exceeding two centimeters in length, *Boraras merah* contributes a negligible biological load to the aquarium. However, because they must be kept in sizable groups to thrive, the overall filtration system should be efficient yet gentle. Sponge filters or air-driven systems are ideal to prevent these tiny fish from being sucked into the filter intake while maintaining excellent water quality free of harmful nitrogenous compounds.

Flow

Strong

Hailing from sluggish peat swamps and slow-flowing forest streams, this species prefers weak to moderate water flow. A strong current will quickly exhaust these tiny fish, forcing them to constantly battle the flow and causing severe stress. Using a filter output directed against the glass or baffled by dense plants helps create calm zones where the fish can rest comfortably.

Jump risk

Yes

While not notorious high-jumpers, *Boraras merah* can easily leap out of the water if startled by sudden movements, lights turning on, or during acclimation. It is therefore essential to provide a tight-fitting lid or cover slides on the aquarium, or utilize a dense cover of floating plants to secure the surface. These measures not only prevent fatal accidents but also make the fish feel secure and less prone to stress-induced flight.

Reproduction

Oviparous

Breeding *Boraras merah* is moderately accessible, as they are egg-scatterers that exhibit no parental care and spawn continuously. While some fry may survive in a mature, densely planted community tank, a dedicated breeding setup with soft, acidic water is recommended for higher yields. The adult pair or group should be removed shortly after spawning to prevent them from eating the eggs, and the fry must be fed microscopic foods like infusoria or paramecia initially.

Compatibility & tankmates

Peaceful

This tiny cyprinid is perfect for species-only setups or community tanks populated by similarly small, peaceful tankmates. Excellent companions include other *Boraras* species, micro-rasboras, dwarf corydoras, freshwater shrimp like *Neocaridina*, and peaceful snails. It is imperative to avoid keeping them with large, aggressive, or hyperactive fish that could easily mistake them for food or stress them out.

Tank level

Top/Middle

Within the aquarium, the Phoenix rasbora prefers to occupy the middle and upper levels of the water column. In these areas, they swim in coordinated shoals under the safety of plant cover or floating vegetation that diffuses the light. Despite this preference, they are curious explorers and will occasionally venture to the bottom of the tank to forage for food scraps among the substrate and decor.