Pygmy rainbowfish

Melanotaenia pygmaea

Also known as Prince Regent rainbowfish

FreshwaterFish

Pygmy rainbowfish (Melanotaenia pygmaea) — Andrewbogott · CC BY-SA 4.0

Care at a glance

Temperature: 73–84°F (23–29°C)
pH: 6.5–7.8
Adult size: 2.4 in (6 cm)
Minimum tank: 20 gal (75 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Rare
Origin: Prince Regent River, Kimberley, Western Australia
Family: Melanotaeniidae

Overview

A true small-tank rainbowfish, kept in a school of eight or more where a group makes a complete little display. It is peaceful and best suited to gentle, small tankmates rather than larger or boisterous fish. Feed fine foods: crushed flake, small granules, and frozen or live daphnia, cyclops, and baby brine shrimp. A group of ten fits comfortably in around 75 liters, with plants and open swimming lanes and bright morning light to bring out the blue.

In the wild

The pygmy rainbowfish lives in the Prince Regent River and nearby streams in the remote Kimberley of Western Australia, gorge country far from any road. Keep it at 23 to 29 degrees Celsius in soft to moderately hard water around neutral, a pH of 6.5 to 7.8. A planted tank scaled to its small size, with driftwood and open water, suits it.

Good to know

Melanotaenia pygmaea, family Melanotaeniidae, was described by Gerald Allen in 1978 and stays around 6 centimeters, the smallest species in its genus. It is silvery blue with a dark, brightly edged band along the side. Breeding is of medium difficulty: the fish scatters adhesive eggs among fine plants or mops, and the very small fry need patient rearing on tiny foods.

Did you know

It is the dwarf of its genus, and its home in the Prince Regent River is so remote that the area remains roadless wilderness, part of a protected reserve reached mainly by boat or aircraft.