Product Details

Aru Rainbowfish – Melanotaenia picta

The Aru Rainbowfish is a rare and beautiful rainbowfish from the Aru Islands, known for its metallic body sheen, active swimming and colourful mature males. Correctly listed as Melanotaenia picta, this species is also called the Painted Rainbowfish and has appeared in the hobby under Aru locality names. It is peaceful with suitable tank mates, but it is an active shoaling fish that needs a mature aquarium with clean water, open swimming room and a proper group.

Key Identification:

Common Name: Aru Rainbowfish
Other Names: Painted Rainbowfish, Aru Painted Rainbowfish, Aru II Rainbowfish, Melanotaenia sp. “Aru II”
Scientific Name: Melanotaenia picta
Fish Type: Rainbowfish / Melanotaeniid
Water Type: Freshwater

Natural Range & Habitat:

Melanotaenia picta is native to the Aru Islands of Indonesia, particularly the Mareremar River system on Kobroor Island. Its natural habitat includes clear rainforest brooks, quiet pools, small cascades, smooth limestone channels and submerged wood or log snags used as shelter.

In the aquarium, Aru Rainbowfish should be kept in a mature, well-filtered setup with open swimming space, planted edges, wood, smooth stones, moderate flow and good oxygenation. A layout with both clear swimming lanes and shaded cover will suit the species well.

Appearance & Adult Size:

Aru Rainbowfish have a streamlined, laterally compressed rainbowfish body with metallic colour that improves as the fish mature. Males may show blue-grey, green, yellow, orange, red or coppery tones depending on sex, age, mood, lighting and breeding line. Females are usually slimmer and more subtly coloured, but still attractive in a settled group.

Adults usually reach around 8–10 cm, with males typically larger and more colourful than females. Young fish can appear plain at first, with the best colour developing as mature males settle and begin displaying.

Aquarium Suitability:

This species is best suited to larger peaceful community aquariums, planted rainbowfish displays and specialist Aru Islands or New Guinea-style setups. It needs open midwater swimming space, stable water quality and calm but confident tank mates.

Aru Rainbowfish are not suitable for tiny aquariums, shy nano communities, aggressive cichlid tanks, predator aquariums or cramped layouts with little swimming room. They are peaceful, but their constant movement can intimidate very small or nervous fish.

Recommended Aquarium Size:

A practical minimum is 150–180 litres for a group, with a tank length of at least 90–100 cm recommended. Larger aquariums of 200 litres or more are preferred for mature groups, mixed rainbowfish displays and stronger long-term colour development.

Keep in a group of at least 6, with 8 or more preferred. A mixed-sex group is ideal, as males show stronger colour and display behaviour when females and rival males are present.

Water Conditions:

Temperature: 22–26°C
pH: 6.8–7.8
Hardness: Moderately soft to moderately hard
Additional Notes: Keep water clean, stable and well oxygenated. Avoid poor oxygenation, high nitrate and sudden water-chemistry swings. This species should not be kept in very soft, unstable water; neutral to slightly alkaline conditions with regular water changes are a good target.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Aru Rainbowfish are peaceful but active community fish. Suitable tank mates include other rainbowfish of similar size, larger peaceful tetras, danios, robust rasboras, peaceful barbs, Cory-type catfish in compatible temperatures, bristlenose plecs and other confident community species.

Avoid very small nano fish, shy slow feeders, delicate long-finned fish, large predators and aggressive cichlids. Adult rainbowfish may eat very small fry or tiny shrimp, so they are not ideal for shrimp-breeding aquariums.

Feeding:

Aru Rainbowfish are easy-feeding omnivores. Offer quality flakes, small floating or slow-sinking granules and rainbowfish pellets as the staple diet. Supplement with frozen or live foods such as daphnia, cyclops, brineshrimp, mosquito larvae, bloodworm and small insect-based foods.

A varied diet helps support colour, body condition and display behaviour. Feed small amounts that are eaten quickly, as active rainbowfish have strong appetites and do best with clean water.

Behaviour in the Aquarium:

This is an active midwater swimmer that spends much of the day moving through open areas of the aquarium. Males may display to females and rival males by intensifying colour, raising fins and making short chasing movements. This is normal in a suitable group and usually does not cause harm when enough space is provided.

Aru Rainbowfish are egg scatterers. Females deposit adhesive eggs among fine plants, mosses or spawning mops, and adults do not provide parental care. Fry require separate rearing if breeding is intended.

Care Notes:

Add Aru Rainbowfish only to a mature, fully cycled aquarium. Provide open swimming room, stable water quality and a secure lid, as active rainbowfish can jump when startled. Avoid overcrowding, poor oxygenation and long periods without water changes.

Do not mix Aru forms with other Melanotaenia picta or closely related rainbowfish locality strains if breeding for line purity. Keeping locality forms separate helps preserve clear, traceable aquarium lines and prevents accidental mixing between strains.

Recommended For:

Intermediate

Availability:

Occasional / Specialist rainbowfish strain, usually captive-bred when available

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, body colour, metallic sheen, fin colour, sex, age and markings can occur between individual fish.