All fish / Nothobranchiidae

Nothobranchius geminus

Nothobranchius geminus

Also known as geminus nothobranchius, twin nothobranch, n. geminus

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This is a small annual killifish from seasonal pools in Tanzania. Males have bluish scales with red edging and red-patterned unpaired fins, while females are plain brownish grey. Killifish enthusiasts keep it for the bright colours of the males and to help keep collection lines going.

Care at a glance

Care level

Moderate

Temperament

Semi

Adult size

4.5 cm

Temperature

20 to 26 °C

pH

6.5 to 7.5

Smallest tank

20 litres

Keep as

One male with two or three females

Diet

Carnivore: live and frozen bloodworm, daphnia, brine shrimp and mosquito larvae

Swims

Middle of the tank

Lifespan

1 year

Water

Freshwater

Wild range

Tanzania (Wami River basin and nearby coastal plains)

Breeding

Pairs or trios lay eggs in peat on the bottom. The peat is then stored damp for several months before being soaked again to hatch the fry. Breeding is fairly straightforward for anyone used to annual killifish, but the eggs must be stored with care.

Good to know

Males fight with each other and the fish lives for only about a year, so keep breeding it to maintain the line. It is listed as Vulnerable by the IUCN and looks very similar to its close relatives, so keep collection location codes with your stock.