Blue Rainbowfish

Blue Rainbowfish (Melanotaenia lacustris), is a beautiful freshwater schooling fish prized for its striking blue coloration, active personality and peaceful nature. It is an excellent choice for larger community aquariums and is particularly impressive when kept in a group.

Blue Rainbowfish are native to Lake Kutubu and surrounding waterways in Papua New Guinea. They inhabit clear freshwater environments with aquatic vegetation.

Adult Blue Rainbowfish have an attractive blue to turquoise body, often with darker markings along the midline. Mature males generally develop stronger coloration and a deeper, more robust body shape, particularly when displaying to females or competing with other males. Juveniles display very little to no colour.

Their coloration can become especially vibrant when they are kept in good water quality, provided with a varied diet and maintained in a suitable group.

Blue Rainbowfish can reach approximately ±10 cm in length, with males typically becoming larger and more robust than females.

They should ideally be kept in a group of at least 4 individuals, with larger groups often producing more natural behaviour and better coloration. Males may display to one another, but this is generally harmless and can be fascinating to watch.

Blue Rainbowfish are omnivores and should be offered a varied diet.

A varied diet helps maintain health, growth and vibrant coloration.

Good water quality and regular maintenance are important for keeping Rainbowfish healthy and displaying their best colours.

Blue Rainbowfish are peaceful and can be kept with a variety of similarly sized community fish. Suitable tank mates can include other Rainbowfish, peaceful barbs, larger tetras, Corydoras and other peaceful freshwater species.

Young specimens may not show their full adult coloration immediately; colour generally becomes stronger as the fish mature.

Provide excellent water quality, a varied diet, adequate swimming space and plenty of oxygenation for the best results.

Blue Rainbowfish are egg-scattering fish. During spawning, females release eggs among fine-leaved plants, spawning mops or other suitable surfaces while males fertilise them.