Black Pearlfish (Cynolebias nigripinnis) — 2,5-4cm

Overview

The Black Pearlfish (Cynolebias nigripinnis) is a striking, short-lived annual killifish native to seasonal freshwater habitats in Brazil. Reaching 4cm in length, this peaceful species is prized for its dark pearly colouration and fascinating breeding behaviour. As an annual killifish, Cynolebias nigripinnis has a compressed life cycle adapted to temporary pools that dry seasonally, making it a captivating choice for experienced aquarists. Available for sale UK from Tropical Fish Co, this rare species rewards dedicated keepers with unique behaviour and stunning appearance in species-only aquariums.

Appearance and Coloration

The Black Pearlfish displays dramatic dark colouration with a compact, robust body adorned in deep blacks and blues with pearl-like iridescent spots scattered across the scales. Males are more intensely coloured than females, with more pronounced finnage and a bolder presence. The fins often feature subtle blue or purple highlights that shimmer under subdued lighting. Females are smaller, plumper, and more subdued in colour, with less pronounced finnage. In a planted tank with dark substrate, the pearly spots become even more visible and eye-catching.

Natural Habitat

Cynolebias nigripinnis inhabits seasonal freshwater pools, wetlands, and temporary water bodies in Brazil. These habitats are characterised by soft, slightly acidic water, abundant vegetation, and a substrate of mud and organic debris. During the wet season, these pools fill with water and the fish spawn rapidly; during the dry season, the pools dry up completely, and the fish perish while their eggs remain dormant in the dried substrate, hatching when the rains return. This annual life cycle is fundamental to the species' biology and behaviour.

Aquarium Setup

A minimum 40-litre aquarium is recommended for a pair or small group of Black Pearlfish. Use a fine sand or soft peat substrate to replicate the natural spawning medium. Include live plants such as Cryptocoryne, Java moss, and floating species like Salvinia or Limnobium. Provide spawning mops or peat moss for egg deposition. Lighting should be subdued, and filtration gentle to avoid strong currents. A secure, tight-fitting lid is essential, as these fish are active and may jump. Maintain excellent water quality, as annual killifish are sensitive to pollution.

Feeding and Diet

As a carnivore, Cynolebias nigripinnis requires a varied, protein-rich diet to maintain health and colour. Offer small live or frozen meaty foods such as daphnia, brine shrimp, mosquito larvae, and bloodworms daily. High-quality micro-pellets may be accepted after acclimation, but live and frozen foods are preferred and essential for conditioning and breeding. Feed small portions twice daily, removing uneaten food promptly to maintain pristine water quality. Variety and freshness are critical for optimal health and vibrant colouration.

Behaviour and Temperament

The Black Pearlfish is a peaceful species that spends most of its time exploring the lower and middle water column. Males may display to each other during courtship, but serious aggression is rare. These fish have a naturally short lifespan of typically 6-12 months, reflecting their annual biology. They are most active during the day and appreciate a dimly lit aquarium with plenty of cover. They are not competitive feeders, so avoid housing them with boisterous or fast-moving species.

Suitable Tank Mates

Cynolebias nigripinnis is best kept in a species-only setup to accommodate its unique breeding biology and short lifespan. Avoid large fish, aggressive fish, fast competitive feeders, fin-nippers, and shrimp or very small invertebrates that may be eaten. A calm, quiet environment is essential for this delicate annual killifish to thrive and complete its natural breeding cycle.

Breeding

This annual killifish typically lays eggs in peat or similar spawning media. Condition a pair or small group with high-quality live foods, then provide spawning media such as peat moss or fine sand. Eggs are buried in the substrate and often require a drying/incubation period of several weeks to months before hatching when water is reintroduced. Collect eggs carefully and store in slightly damp peat in a sealed container. Fry hatch when the peat is re-flooded and require infusoria or newly hatched brine shrimp. Breeding success depends on matching seasonal conditions and careful egg management.

Why Buy from Tropical Fish Co

Tropical Fish Co is a trusted UK supplier of rare and specialist tropical fish, including hard-to-find annual killifish species like Cynolebias nigripinnis. We guarantee healthy, well-conditioned stock, expert care advice, and secure nationwide delivery. Every fish is quarantined and inspected before dispatch, ensuring you receive only the finest specimens. Whether you're setting up a dedicated killifish tank or adding a rare species to your collection, Tropical Fish Co offers unmatched quality and customer service. Order online today and experience the fascinating world of annual killifish.