Species description

Care, breeding and tankmates

Fish profile

Temperament

Semi-aggressive

This species is exceptionally peaceful but highly timid and delicate. They are easily intimidated by larger or more active fish, which can lead to severe stress and starvation. It is essential to keep them in a dedicated species-only aquarium or alongside very peaceful nano-fish. They thrive best in quiet environments where they can display their natural schooling behaviors without disturbance.

Diet

Carnivore

In their natural habitat, they are micro-predators feeding on zooplankton, tiny insect larvae, and microscopic aquatic invertebrates. In the aquarium, they should be offered small live or frozen foods such as baby brine shrimp, cyclops, and daphnia. High-quality powdered or crushed dry foods may be accepted over time, but should not form the bulk of their diet. A varied diet of tiny, nutrient-dense foods is crucial to maintain their health and vibrant color.

Life expectancy

3-5 years

In captivity under optimal conditions, Brittanichthys myersi has a lifespan of approximately 3 to 5 years. Achieving this lifespan requires maintaining highly stable, acidic blackwater parameters and providing a varied diet. Chronic stress from inappropriate tank mates or fluctuating water conditions will drastically reduce their longevity. Excellent husbandry practices and clean water are key factors in maximizing their lifespan.

Sex ratio

Group

This species is shoaling and should be kept in mixed-sex groups of 8 or more individuals. A balanced sex ratio is ideal, though exact male-to-female ratios are not strictly required for their well-being. Keeping a larger group helps diffuse potential territorial behavior or mating pursuit stress among males. A school will exhibit more natural behavior and brighter coloration when kept in numbers.

Feeding frequency

Twice daily

Due to their tiny size and fast metabolism, Brittanichthys myersi should be fed small quantities multiple times a day. Two to three daily feedings of tiny portions are ideal to prevent muscle wasting and maintain energy. Care must be taken not to overfeed, as uneaten food will quickly spoil their sensitive water environment. Providing food in small increments allows all individuals in the school to eat.

Bioload

Low

Brittanichthys myersi is a tiny characin with an extremely low individual biological footprint. However, because they must be kept in groups of at least 8 to 10 individuals to feel secure, their collective bioload should be accounted for. They are highly sensitive to accumulation of organic waste, requiring robust filtration and consistent water quality. Regular small water changes are recommended over large, disruptive ones to maintain stable parameters.

Flow

Stagnant

This species originates from slow-moving blackwater streams and flooded forest areas in the Rio Negro basin. Consequently, they require very gentle water flow in the aquarium, as strong currents will quickly exhaust them. Filtration should be adjusted or baffled to minimize surface and midwater agitation. Air-powered sponge filters or gentle hang-on-back filters with pre-filter sponges are highly recommended for their setup.

Jump risk

Yes

Like many small and agile characins, Brittanichthys myersi poses a moderate risk of jumping, especially when startled. They can easily leap out of open aquarium setups during water changes or when lights are turned on suddenly. A tight-fitting lid or a mesh cover is highly recommended to prevent accidental escapes. The inclusion of floating plants can also help deter jumping by providing surface cover.

Reproduction

Oviparous

Brittanichthys myersi is a unique inseminating characin that exhibits internal fertilization. Males possess modified anal fin rays that form a specialized structure used to transfer sperm to the female. Females store the sperm and lay fertilized eggs later, a reproductive trait that distinguishes them from most other tetras. Breeding in captivity is extremely difficult and rarely documented, requiring pristine, extremely soft, and acidic blackwater conditions.

Compatibility & tankmates

This species is ideal for species-only setups or specialized nano blackwater aquariums. They should only be housed with very small, peaceful tank mates such as pygmy corydoras, small loricariids, or other gentle micro-characins. Larger, active, or boisterous fish must be strictly avoided as they will easily outcompete and stress this timid species. Keeping them with too many active species may cause them to remain hidden and waste away.

Tank level

Middle/Bottom

Brittanichthys myersi typically occupies the middle to lower regions of the water column. They prefer swimming among the dense foliage of plants and roots, rarely venturing to the surface. Providing floating plants will help shade the tank and encourage them to utilize the middle areas more actively. Their benthopelagic nature means they will spend most of their time darting through lower aquatic vegetation.