TankBud

Dwarf rainbowfish

Melanotaenia maccullochi

Also known as MacCulloch's rainbowfish, Maccullochi Rainbow

FreshwaterFish

Dwarf rainbowfish (Melanotaenia maccullochi)
Imperial Tropicals · Used with permission

Care at a glance

Temperature
72–82°F
22–28°C
pH
5.5–7.5
Adult size
2.8 in
7 cm
Minimum tank
20 gal
75 L
Temperament
Peaceful
Social behavior
Schooling
Swim level
Middle
Difficulty
Easy
Breeding
Egg scatterer · Medium
Rarity
Common
Family
Melanotaeniidae
Origin
Northeastern Australia and southern Papua New Guinea

Overview

The dwarf rainbowfish is a small, active and peaceful schooler for the middle of a planted community tank. It is easy to keep, even for a beginner.

Did you know

A dwarf rainbowfish's color builds with age and mood. A young or stressed fish can look washed out next to a settled adult.

Caring for the dwarf rainbowfish

Lone dwarf rainbowfish and small groups tend to be skittish, so keep six to eight together in at least 20 gal (75 L). Give them a planted tank with some driftwood and clear, open lanes through the middle. Keep the flow slow, and use a darker substrate to bring out their color.

Dwarf rainbowfish are very adaptable on water chemistry. They handle a wide range, 72 to 82°F (22 to 28°C) and a pH of 5.5 to 7.5, if it stays stable. Feed small flakes, micro pellets and frozen foods such as daphnia or baby brine shrimp.

They are active and peaceful, so pair them with other calm, similarly sized fish. Avoid mixing different geographic color forms, so the strains stay clean. Keep more females than males, which keeps the peace and brings out the best display.

Males often deepen their color and spar gently when showing off to females. Dwarf rainbowfish are egg scatterers that drop eggs onto fine plants or spawning mops, with no parental care. Breeding is moderate work, since the tiny fry need infusoria for their first days.

Good to know

The dwarf rainbowfish belongs to the rainbowfish family Melanotaeniidae, and a healthy fish lives several years. Most stock in the trade is tank bred. It is also known as MacCulloch's rainbowfish.

In the wild

Dwarf rainbowfish come from slow streams, swamps and pools across northeastern Australia and southern Papua New Guinea. These waters often run over leaf litter and tangled plant growth.

Weekly picks

Tank mates

The dwarf 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 a dwarf rainbowfish need?

A dwarf rainbowfish needs at least 20 gal (75 L). It spends most of its time in the middle.

What temperature and pH does a dwarf rainbowfish need?

A dwarf rainbowfish is comfortable at 72–82°F (22–28°C) with a pH of 5.5–7.5.

What does a dwarf rainbowfish eat?

A dwarf rainbowfish eats small flakes, micro pellets and frozen foods such as daphnia or baby brine shrimp.

How big does a dwarf rainbowfish get?

An adult dwarf rainbowfish reaches about 2.8 in (7 cm).

Does a dwarf rainbowfish need a group?

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

How does a dwarf rainbowfish breed?

Dwarf rainbowfish scatter their eggs onto fine plants or spawning mops and give no parental care. Breeding is moderate work, because the tiny fry need infusoria for their first days.

Related species