Argentine Pearl Killifish

Care at a glance

Overview

This annual killifish is best kept as a single male with two or three females in a quiet, soft-water tank with plenty of planting and cover. Males court constantly and can wear down a lone female, so extra females spread the attention. It is a keen predator that wants live and frozen foods like bloodworms, blackworms, daphnia and brine shrimp, and usually ignores flake. It lives in the middle and lower water and does best kept cool, ideally in the lower part of its range. A tank of 70 liters or larger is enough for a trio, with a soft substrate for spawning.

In the wild

The Argentine pearl killifish lives in temporary pools and flooded grassland across the lowlands of Argentina and Uruguay. These pools fill with the seasonal rains, warm and cool through the year, and then dry out completely, so the adults live fast and die within a single season. Recreate a soft, slightly acidic pool with tannin-stained water, gentle filtration and a deep layer of peat or fine substrate for spawning. It is a subtropical fish that prefers cool water around 18 to 24 C, well below the tropical killifish.

Good to know

Austrolebias nigripinnis is a South American annual killifish in the family Rivulidae, reaching about 6 to 7 cm, with dark, pearl-spangled males. As an annual species it survives the dry season only as eggs, which the adults bury in the soft bottom before the pool disappears. The eggs pass through resting phases called diapause and hatch when they are wetted again. Breeding is demanding because it means managing the substrate, drying the eggs for the right period and then triggering a clean hatch.

Did you know

Argentine pearl killifish complete their whole lives in seasonal pools that vanish each dry season. The parents die when the water goes, but their eggs rest in the dried mud through diapause and hatch when the rains return.

Related species

• Argentine pearlfish

  Austrolebias bellottii

  2.8 in (7 cm)14 gal (54 L)61–75°F (16–24°C)
• Rio pearlfish

  Nematolebias whitei

  3.1 in (8 cm)14 gal (54 L)68–77°F (20–25°C)

• 

  Magnificent killifish

  Hypsolebias magnificus

  2 in (5 cm)10 gal (38 L)72–79°F (22–26°C)

• 

  Fighting gaucho

  Cynopoecilus melanotaenia

  1.8 in (4.5 cm)5 gal (20 L)64–75°F (18–24°C)

• 

  Dwarf rainbowfish

  Melanotaenia maccullochi

  2.8 in (7 cm)20 gal (75 L)72–82°F (22–28°C)

• 

  Glass catfish

  Kryptopterus vitreolus

  2.8 in (7 cm)30 gal (115 L)70–79°F (21–26°C)