Elongate Pearlfish

Pterolebias longipinnis is one of the most visually dramatic annual killifish in the hobby, native to seasonal pools and flooded savannah habitats in Brazil and Argentina. Adult males develop enormously elongated dorsal and caudal fin extensions that flow like a veil, combined with vivid blue-grey and orange colouration, making them among the most spectacular killifish available to aquarists. Females are much plainer but essential breeding partners.

As an annual killifish, P. longipinnis requires a dedicated 80 L species tank with deep peat substrate for egg deposition. Soft, acidic water is essential, and the tank should be maintained at temperatures reflecting the warm South American savannah conditions. Eggs require a mandatory diapause of 10–14 weeks in slightly moist peat. Males are territorial and should be housed one per tank.

P. longipinnis is a premier annual killifish for the serious collector. Its extraordinary fin development, large size, and dramatic colouration place it among the most visually striking freshwater fish available. Maintaining this species successfully is a significant achievement in the killifish hobby.

Water: 20–26 °C, pH 5.5–7.0, very soft water (GH 1–6) essential for breeding. Tank: 80 L species tank with 5–8 cm deep peat substrate; males need space to display. Feeding: Live and frozen Artemia, Daphnia, bloodworm, and earthworms for large adults; feed daily. Breeding: Harvest peat every 4 weeks; store eggs 10–14 weeks in moist peat before re-wetting. Compatibility: Species tank only; male fin extensions are vulnerable to damage from any tankmates.