All fish / Rivulidae

Black-finned Pearlfish

Austrolebias nigripinnis

Also known as black-fin pearl killifish, blackfin pearlfish, black finned pearl fish, argentine pearlfish, cynolebias nigripinnis, nigripinnis killifish, black pearl killi, オーストロレビアス・ニグリピニス, 黑鳍珍珠鳉

Males are a deep blue-black covered in pale blue-green pearly spots, with large rounded dorsal and anal fins, while females are smaller and brownish with darker blotches. It is an annual killifish from temporary pools and is kept by killifish enthusiasts for the striking colour of the males and its unusual life cycle.

Care at a glance

Care level

Moderate

Temperament

Semi

Adult size

4 cm

Temperature

16 to 24 °C

pH

6 to 7.5

Smallest tank

30 litres

Keep as

One male with two or three females

Diet

Carnivore: live and frozen bloodworm, daphnia, brine shrimp and mosquito larvae; dry food is often refused

Swims

Middle of the tank

Lifespan

Under 1 year, sometimes up to 18 months

Water

Freshwater

Wild range

Lower Paraná and Uruguay river basins in Argentina and Uruguay

Breeding

A soil-diving annual species that lays its eggs in soft peat, which is then removed and stored slightly damp for about three to five months before being rewetted to hatch. Breeding is not difficult once you have the peat incubation routine sorted, and the fry grow very quickly on newly hatched brine shrimp.

Good to know

Males fight one another and can wear females out, so give plenty of cover and do not crowd several males together. It prefers cool water and lives only a short time, so keep it going by breeding it regularly rather than as a long-term community fish.