All fish / Melanotaeniidae

New Guinea Rainbowfish

Melanotaenia affinis

Also known as new guinea rainbowfish, north new guinea rainbowfish, affinis rainbowfish, pagai rainbowfish, bewani rainbowfish, red fin rainbowfish, メラノタエニア・アフィニス, ikan pelangi, 新几内亚彩虹鱼

A lively, deep-bodied rainbowfish with a silvery to bluish body, a dark lateral stripe and fins edged in red, orange or yellow depending on the population. Males become deeper bodied and more colourful with age, and a group makes an active, hardy centrepiece for a planted community tank.

Care at a glance

Care level

Easy

Temperament

Peaceful

Adult size

10 cm

Temperature

22 to 28 °C

pH

6.5 to 8

Smallest tank

200 litres

Keep as

Shoal of 6 or more, ideally with more females than males

Diet

Omnivore: quality flakes and granules, frozen bloodworm, brine shrimp and daphnia, plus some plant matter

Swims

Middle of the tank

Lifespan

5 to 8 years

Water

Freshwater

Wild range

Northern New Guinea (Sepik and Ramu river basins, Papua New Guinea and Papua, Indonesia)

Breeding

An egg scatterer that lays a few eggs daily over several days among fine-leaved plants or spawning mops. It breeds readily in captivity; move the eggs or the adults out, then raise the fry on infusoria before moving them on to baby brine shrimp.

Good to know

Several local forms exist, so keep each population separate and avoid crossing it with other Melanotaenia species. Adults need a long tank with plenty of swimming space and a tight lid, as they will jump.