Red-Finned Pearl Fish (Cynolebias heloplites) — 3-4cm

Overview

The Red-Finned Pearl Fish (Cynolebias heloplites) is a striking, short-lived annual killifish native to seasonal freshwater pools and wetlands in South America, likely Brazil. Reaching 4cm in length, this peaceful species is prized for its vivid red fins and fascinating breeding behaviour. As an annual killifish adapted to temporary habitats that dry seasonally, Cynolebias heloplites has a compressed life cycle and unique reproductive biology. Available for sale UK from Tropical Fish Co, this rare species rewards experienced keepers with spectacular colouration and captivating behaviour in species-only aquariums.

Appearance and Coloration

The Red-Finned Pearl Fish displays stunning colouration with a compact, robust body adorned in soft blues and greens with pearl-like iridescent spots scattered across the scales. The most striking feature is the vivid red finnage—particularly the dorsal, anal, and caudal fins—that creates a dramatic contrast against the body. Males are intensely coloured with pronounced red finnage and a bold presence, especially during courtship. Females are smaller, plumper, and more subdued in colour with less pronounced red colouration. In a planted tank with dark substrate, the red fins become even more vibrant and eye-catching.

Natural Habitat

Cynolebias heloplites inhabits seasonal freshwater pools and wetlands in South America, likely Brazil, though the exact range is not well documented in the aquarium trade. These temporary water bodies fill with water during the wet season and dry completely during the dry season. The water is typically soft, slightly acidic to neutral, and well-vegetated, with a substrate of mud and organic debris. During the wet season, adults spawn rapidly; as pools dry, adults perish while eggs remain dormant in dried substrate, hatching when rains return.

Aquarium Setup

A minimum 40-litre aquarium is recommended for a pair or small group of Red-Finned Pearl Fish. 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 jumping risk is high. Maintain excellent water quality and cooler temperatures (20-24°C) to replicate natural conditions.

Feeding and Diet

As a carnivore, Cynolebias heloplites requires a varied, protein-rich diet to maintain health and colour. Offer small live and frozen meaty foods such as daphnia, brine shrimp, mosquito larvae, and bloodworms daily. High-quality carnivorous micro-pellets may be accepted after acclimation. Live and frozen foods are essential for conditioning and breeding, and help maintain the vivid red fin colouration. Feed small portions twice daily, removing uneaten food promptly to maintain pristine water quality.

Behaviour and Temperament

The Red-Finned Pearl Fish 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 with flared red fins and vibrant colour displays, but serious aggression is rare. These fish have a naturally short lifespan of typically 6-12 months, reflecting their annual biology. They 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 heloplites is best kept in a species-only setup to accommodate its unique breeding biology and short lifespan. Other small, peaceful annual killifish may be suitable only if tank size and breeding behavior are carefully managed. Avoid large fish, fast-feeding community fish, aggressive fish, fin-nipping species, and shrimp or very small invertebrates that may be eaten. A calm, quiet environment is essential for this delicate annual killifish to thrive.

Breeding

This annual killifish typically breeds by laying eggs in soft substrate or peat. Condition a pair or small group with high-quality live foods, then provide spawning media such as peat moss or fine sand. Eggs often require a drying/incubation period before hatching, and successful breeding depends on precise water conditions and careful egg management. Collect eggs carefully and store in slightly damp peat in a sealed container at cool room temperature. Fry hatch when the peat is re-flooded and require infusoria or newly hatched brine shrimp.

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 heloplites. 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 beauty of South American annual killifish.