TankBud

Australian rainbowfish

Melanotaenia fluviatilis

FreshwaterFish

Australian rainbowfish (Melanotaenia fluviatilis)
Bahudhara · CC BY-SA 3.0

Care at a glance

Temperature
68–77°F
20–25°C
pH
6.5–8.0
Adult size
4.3 in
11 cm
Minimum tank
30 gal
115 L
Temperament
Peaceful
Social behavior
Schooling
Swim level
Middle
Difficulty
Medium
Breeding
Hard
Rarity
Rare
Family
Melanotaeniidae
Origin
Australia

Overview

Keep Australian rainbowfish in a group of at least six, and a larger shoal brings out the best color as the males display and chase among themselves. They spend most of their time in the middle of the tank and stay peaceful with other calm community fish of a similar size. Males take a year or more to develop their full silver and orange finnage, so feeding well and giving them space matters. Offer a quality flake or small pellet along with frozen bloodworms, daphnia, and brine shrimp. Plant the sides and back and leave open water down the center for swimming. Aim for a tank around 115 liters or larger.

In the wild

This species comes from the Murray-Darling river system and other inland waters of eastern Australia, where it lives in flowing streams, billabongs, and quiet pools. The water there is often clear and on the harder, neutral to slightly alkaline side, which matches a pH of about 6.5 to 8. It also handles a cooler range than most rainbowfish, sitting comfortably between 20 and 25 degrees Celsius. Recreate it with a sandy or fine gravel bed, some driftwood, hardy plants around the edges, and steady, well-oxygenated water with gentle flow.

Good to know

The Australian rainbowfish belongs to Melanotaeniidae, the rainbowfish family of Australia and New Guinea. It grows to around 11 centimeters, with males deeper bodied and more strongly colored than the slimmer females. Like its relatives it is an egg-scatterer that spawns over a long season rather than in one event, releasing a few sticky eggs each day that catch on fine-leaved plants or spawning mops by short threads. The eggs take about a week to hatch. Establishing a settled breeding group takes patience, which is part of why home breeding is rated as hard.

Did you know

The species name fluviatilis means of the river, a nod to its home in the Murray-Darling, the largest river system in Australia. It is one of the more cold-tolerant rainbowfish and can sit through cool spells that would stress its tropical cousins.

Weekly picks

Tank mates

Australian rainbowfish is a peaceful, schooling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does an Australian rainbowfish need?

An Australian rainbowfish needs at least 30 gal (115 L). It spends most of its time in the middle.

What temperature and pH does an Australian rainbowfish need?

An Australian rainbowfish is comfortable at 68–77°F (20–25°C) with a pH of 6.5–8.0.

How big does an Australian rainbowfish get?

An adult Australian rainbowfish reaches about 4.3 in (11 cm).

Does an Australian rainbowfish need a group?

Yes. An Australian rainbowfish is a schooling species and should be kept in a group, not singly.

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