Aru Rainbowfish Care Guide - Aquarium Setup, Diet & Breeding

Aru Rainbowfish are elegant, active fish with the deep-bodied profile typical of the Melanotaeniidae family. Their coloration can include olive, blue-green and silvery tones, often enhanced by warm orange, reddish or golden markings toward the flanks and fins. Mature males usually develop the strongest colour and a deeper body shape, particularly when displaying to females or competing with other males.

They are lively but generally peaceful community fish, spending much of their time in the middle and upper levels of the aquarium. A group creates a more natural display, with males regularly facing one another and showing their colours without normally causing serious injury.

In the wild, this species is associated with the varied freshwater habitats of the Aru Islands, including slow-moving channels, pools and wetland environments. These waters may be bordered by dense vegetation, submerged roots and leaf litter, providing cover as well as areas of open water for feeding and courtship.

Aru Rainbowfish are less commonly encountered than several of the better-known Australian and New Guinean rainbowfish. Their active nature, attractive adult males and interest in group behaviour make them a rewarding choice for aquarists who can provide a spacious, well-maintained aquarium.

Aru Rainbowfish, Melanotaenia picta, are native to the Aru Islands of southeastern Indonesia, an island group in the Arafura Sea between New Guinea and northern Australia. They inhabit freshwater streams, pools and swamp-associated waters on the islands.

A group should be given at least 120 litres, with a tank around 90 cm long or larger to provide useful swimming space; a longer aquarium is preferable for active adults. Use an open central area for movement, backed by dense plants, floating cover, driftwood or smooth roots around the edges. A dark sand or fine gravel substrate can bring out their colours, while gentle to moderate water movement, secure cover and efficient filtration create a suitable setup. Leave enough surface area for their active midwater behaviour and jumping ability.

Up to about 10 cm (4 in) in total length. Males are usually larger and deeper-bodied than females, while females commonly remain slightly smaller and slimmer.

These omnivorous fish benefit from a varied diet of quality flakes and small pellets supplemented with frozen or live foods such as brine shrimp, daphnia, bloodworm and mosquito larvae. Small portions of vegetable matter, including spirulina-based foods or finely softened greens, help provide balance. Feed modest amounts regularly so every fish can eat without leaving excessive food in the aquarium.

Aru Rainbowfish generally suit peaceful community aquariums containing similarly sized, active fish. Suitable companions include other peaceful rainbowfish, larger peaceful tetras, danios, rasboras, Corydoras, peaceful loaches and small to medium-sized peaceful gouramis. Avoid very small, slow-moving or long-finned fish that may be unsettled by their activity, as well as fin-nipping species, highly aggressive cichlids and fish small enough to be swallowed. They are best kept in a group of their own kind rather than as solitary specimens.

Aru Rainbowfish are egg scatterers that can be bred in a separate, mature aquarium furnished with fine-leaved plants or spawning mops. Condition a group with varied, protein-rich foods, then allow a ripe female and several males to spawn over the plants. Remove the spawning material or adults after eggs are laid, as the eggs and fry may be eaten. Hatching usually takes around one to two weeks, and the tiny fry initially need infusoria-sized foods before they can accept newly hatched brine shrimp.

Males are typically more robust, deeper-bodied and more brightly coloured, especially across the flanks and fins. Females are generally slimmer, less intensely marked and may show a more noticeable dark mid-lateral line, although colour varies with age, mood and conditions.