All fish / Melanotaeniidae

Slender rainbowfish

Melanotaenia gracilis

Also known as slender rainbow, slender rainbow fish, drysdale river rainbowfish, メラノタエニア・グラシリス, 细长彩虹鱼

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A slim, active rainbowfish with a silvery body, a bold dark stripe along the flank and red or orange edging on the fins of males. It stays smaller and more streamlined than most of its relatives, so it suits planted community tanks with plenty of open swimming space.

Care at a glance

Care level

Easy

Temperament

Peaceful

Adult size

7 cm

Temperature

22 to 30 °C

pH

6.5 to 8

Smallest tank

110 litres

Keep as

Shoal of 6 or more, with more females than males

Diet

Omnivore: quality flakes and small pellets, frozen bloodworm, brine shrimp, daphnia and some plant matter

Swims

Middle of the tank

Lifespan

4 to 6 years

Water

Freshwater

Wild range

Kimberley region of Western Australia (Drysdale, King Edward and Prince Regent river systems)

Breeding

An egg scatterer that lays adhesive eggs among fine-leaved plants or spawning mops over several days. Breeding is straightforward in captivity, and the tiny fry need infusoria or other very fine foods at first.

Good to know

Do not keep it with other Melanotaenia species, because they can hybridise and wild lineages are prized by hobbyists. It is a strong jumper, so use a tight-fitting lid.