What tank size does a Red Rainbowfish need?

A Red Rainbowfish needs an aquarium of at least 180 litres (47.6 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 Red Rainbowfish need?

Red Rainbowfish does best at 22–30 °C (71.6–86 °F), pH 7–8.2 and a general hardness of 9–20 °dGH.

What group size does a Red Rainbowfish need?

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

Is the Red Rainbowfish suitable for beginners?

Red 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

Red Rainbowfish

Glossolepis incisus

Melanotaeniidae

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

📷 Chrumps · CC BY-SA 4.0 · resized · Wikimedia Commons

Red Rainbowfish — Glossolepis incisus — 📷 Chrumps · CC BY-SA 4.0 · resized · Wikimedia Commons

About

The red rainbowfish is a large, deep-bodied schooling fish endemic to Lake Sentani in Papua, Indonesia. Mature males turn brick to salmon red and develop a strikingly humped back and forehead; females and young males stay olive-silver, which is why shop tanks of small fish look nothing like the adults. Reaching 15 cm and swimming hard all day, it is a big-tank fish: peaceful, but boisterous enough to unsettle small or slow-moving tankmates, and colour only arrives after a year or two of good feeding.

Care

Needs a 120 cm or longer tank of 180 L+ with open swimming space, hard neutral to alkaline water and a group of 6-8 with extra females. Fit a tight lid — rainbowfish jump — and expect full colour to take a year or more.

Diet

Omnivore that grazes insects, zooplankton and plant matter; quality dry food plus frequent frozen or live bloodworm, brine shrimp and daphnia, with occasional greens.

Tankmate compatibility

Gets along with (6)

Boesemani Rainbowfish Celebes Rainbowfish Figure-8 Puffer Rabbit Snail T-Bar Cichlid Wrestling Halfbeak

Possible with care (213)

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Avoid (52)

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 Red Rainbowfish need?: A Red Rainbowfish needs an aquarium of at least 180 litres (47.6 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 Red Rainbowfish need?: Red Rainbowfish does best at 22–30 °C (71.6–86 °F), pH 7–8.2 and a general hardness of 9–20 °dGH.
What group size does a Red Rainbowfish need?: Red Rainbowfish is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.
Is the Red Rainbowfish suitable for beginners?: Red 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

Temperature22–30°C

Optimal temp.25–28°C

pH7–8.2

Hardness (GH)9–20°d

Carbonate (KH)4–15°d

Adult size15 cm

Min. volume≥ 180 L

Min. tank length≥ 120 cm

Group size≥ 6

Swimming zoneMid

TemperamentPeaceful

Water typeFreshwater

FlowModerate

Lifespan~7 yrs

Try in the calculator