Peruvian Longfin (Pterolebias peruensis) — 4-6cm

Overview

The Peruvian Longfin (Pterolebias peruensis) is a striking Peruvian annual killifish native to Peru, South America, where it is typically associated with seasonal freshwater habitats. Reaching 4cm in length, this peaceful species is prized for its elegant long fins and fascinating short-lived breeding biology. As an annual killifish adapted to seasonal habitats, Pterolebias peruensis has a compressed life cycle and unique reproductive biology. Available for sale UK from Tropical Fish Co, this rare species rewards dedicated keepers with spectacular finnage and captivating behaviour.

Appearance and Coloration

The Peruvian Longfin displays elegant colouration with a slender, graceful body adorned in soft greens, golds, and browns with delicate patterning. The most distinctive feature is the elongated, flowing finnage—particularly the dorsal, anal, and caudal fins—that creates a graceful silhouette. Males are more intensely coloured than females, with more pronounced longfin finnage and a bolder presence. Females are smaller, plumper, and more subdued in colour with shorter finnage. In a planted tank with dark substrate, the colours and elegant finnage become even more visible and eye-catching.

Natural Habitat

Pterolebias peruensis is native to Peru, South America, where it is typically associated with seasonal freshwater habitats. These temporary water bodies fill with water during the wet season and may dry or nearly dry during the dry season. The water is typically soft, slightly acidic to neutral, and well-vegetated, with a substrate of mud and organic debris. These surface-oriented fish spend most of their time at or near the water's surface.

Aquarium Setup

A minimum 60-litre aquarium is recommended for a pair or small group of Peruvian Longfin. Use a fine sand or smooth gravel substrate with plenty of live plants such as Cryptocoryne, Java moss, Microsorum, and floating species like Salvinia or Pistia. Provide open swimming space near the surface, as this is a surface-oriented species. 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 this species may jump.

Feeding and Diet

As a carnivore, Pterolebias peruensis requires a varied, protein-rich diet to maintain health and colour. Offer a varied diet of small live and frozen foods such as bloodworms, daphnia, brine shrimp, and insect larvae, supplemented with high-quality carnivore micro-pellets if accepted. Live and frozen foods are essential for conditioning and breeding. Feed small portions once or twice daily, removing uneaten food promptly to maintain water quality.

Behaviour and Temperament

The Peruvian Longfin is a peaceful, surface-dwelling species that spends most of its time patrolling the upper water column in search of food. Males may display to each other with flared fins and subtle posturing, but serious aggression is rare. These fish are most active during dawn and dusk, and they appreciate a dimly lit aquarium with plenty of surface cover. They are not competitive feeders, so avoid housing them with boisterous or fast-moving species. This species is likely short-lived and may be sensitive to stress.

Suitable Tank Mates

Pterolebias peruensis is best kept species-only to accommodate its unique breeding biology and delicate nature. If tankmates are used, only very small, peaceful species that will not compete for food or stress them should be considered. Avoid large fish, fast boisterous fish, aggressive cichlids, fin-nippers, and species that require very hard or alkaline water. A calm, quiet environment is essential for this delicate annual killifish to thrive.

Breeding

This is likely an annual killifish with eggs that may require a drying/incubation period in peat or similar spawning medium before hatching. Condition a pair or small group with high-quality live foods, then provide spawning media such as peat moss or fine sand. Breeding success depends on precise seasonal cues and careful egg management. 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. Provide pristine water and gentle filtration.

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 Pterolebias peruensis. 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 bring the beauty of Peruvian waters into your home aquarium.