What tank size does a Turquoise Rainbowfish need?

A Turquoise Rainbowfish needs an aquarium of at least 150 litres (39.6 US gallons) with a footprint at least 120 cm (47.2 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Turquoise Rainbowfish need?

Turquoise Rainbowfish does best at 20–26 °C (68–78.8 °F), pH 7–8.5 and a general hardness of 8–20 °dGH.

What group size does a Turquoise Rainbowfish need?

Turquoise Rainbowfish is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.

Is the Turquoise Rainbowfish suitable for beginners?

Turquoise Rainbowfish sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Species library

Turquoise Rainbowfish

Melanotaenia lacustris

Melanotaeniidae

FishDifficulty: ●●●○○Data: well-established

Turquoise Rainbowfish — Melanotaenia lacustris — 📷 source not recorded

About

The turquoise rainbowfish is a shimmering blue schooling species found only in Lake Kutubu and its outlet, the Soro River, in the Southern Highlands of Papua New Guinea. Mature males glow an intense cobalt-to-turquoise blue that shifts with light and mood, deepening over the first year of life. Peaceful, fast and endlessly active, it is a superb centrepiece for a long, open community tank and, though endangered in the wild, is widely bred in captivity.

Care

Keep a group of 6 or more (ideally more) in a long tank of at least 120 cm with open swimming space, neutral to alkaline medium-hard water, and a tight lid as these active fish jump. Colour intensifies over many months in a stable, mature setup.

Diet

Micro-omnivore that grazes zooplankton, insects and plant matter in the wild; feed varied dry foods plus regular frozen or live meaty foods for peak colour, with occasional greens or spirulina.

Tankmate compatibility

Gets along with (12)

Assassin Snail Dwarf Orange Crayfish Endler's Livebearer Figure-8 Puffer Forktail Rainbowfish Ghost Shrimp Guppy Mystery Snail Nerite Snail Platy Swordtail Wrestling Halfbeak

Possible with care (203)

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Avoid (56)

Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.

Telling males from females

What works for this species, most reliable first.

Colour and patternStrong · from about 6 months, and only on a settled fish
In rainbowfish, killifish and several barbs the male carries the colour — deeper and more saturated, intensifying further when he displays.

All the methods, with diagrams

Also in these lists

Fish for hard water Peaceful community fish

Frequently asked questions

What tank size does a Turquoise Rainbowfish need?: A Turquoise Rainbowfish needs an aquarium of at least 150 litres (39.6 US gallons) with a footprint at least 120 cm (47.2 in) long — for this species, swimming length matters as much as raw volume.
What water parameters does a Turquoise Rainbowfish need?: Turquoise Rainbowfish does best at 20–26 °C (68–78.8 °F), pH 7–8.5 and a general hardness of 8–20 °dGH.
What group size does a Turquoise Rainbowfish need?: Turquoise Rainbowfish is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.
Is the Turquoise Rainbowfish suitable for beginners?: Turquoise Rainbowfish sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

Water & tank

Temperature20–26°C

Optimal temp.23–26°C

pH7–8.5

Hardness (GH)8–20°d

Carbonate (KH)3–12°d

Adult size11 cm

Min. volume≥ 150 L

Min. tank length≥ 120 cm

Group size≥ 6

Swimming zoneMid

TemperamentPeaceful

Water typeFreshwater

FlowModerate

Lifespan~6 yrs

Try in the calculator