Rio pearlfish

Care at a glance

Overview

Keep a male with two or three females in a 54 litre species tank at 20 to 25 C and pH 6.0 to 7.0. Males display hard at each other, so give plenty of room and cover or keep a single male. Feed rich live and frozen foods such as bloodworm, blackworm, brine shrimp, and daphnia to fuel their fast growth. Spawn them over a peat tray and store the eggs damp for a few months.

In the wild

It lives in small, shallow freshwater pools over soft reddish mud that dry out twice a year on the Rio de Janeiro lowlands. Males are stocky with a blue-green body scattered with pearly white spots and red bars, while females are plain. A dim tank with a deep soft substrate or a peat spawning tray and a tight lid suits it.

Good to know

Nematolebias whitei is unusual in being a twice-yearly, or bi-annual, killifish because its pools dry and refill two times each year rather than once. Its eggs enter diapause in the mud and hatch when the water returns. It is a hardy, prolific species that has become a genome and developmental study model.

Did you know

Because its home pools dry out twice in a year, its eggs are set up to survive two separate dry spells, an unusual trick even among annual killifish.

Related species

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