Parkinson's Rainbowfish (Melanotaenia parkinsoni)

Parkinson's Rainbowfish overview

Parkinson's Rainbowfish (Melanotaenia parkinsoni) is a colourful, active rainbowfish from Papua New Guinea. It is also traded as Parkinsoni Rainbowfish or Orange Rainbowfish because mature males develop glowing orange to golden markings across the rear body and fins, contrasting with a blue-silver front half. This is a lively midwater species for aquarists who can provide space, clean water and a proper shoal.

Choose from the 4-5 cm and 5-7 cm size options shown on this page, checking availability before ordering. These are purchase sizes, not adult sizes.

Quick facts

Natural habitat and identity

FishBase places Melanotaenia parkinsoni in the family Melanotaeniidae and records its natural range in Papua New Guinea between the Kemp Welsh River and Milne Bay. It is associated with lowland rainforest streams, while aquarium references describe seasonal habitats where streams may reduce to pools during the dry season. This background explains why the species is hardy once settled, but still needs excellent water quality and oxygen.

Aquarium setup

Give this fish a long, open aquarium with room to swim. A 150 litre aquarium is the practical starting point for a modest group, and a four-foot tank or larger is better for long-term adult behaviour. Use planting along the back and sides, open swimming space in the centre, a darker substrate if you want colours to stand out, and a secure lid because active rainbowfish can jump.

Filtration should be mature and reliable, with enough movement to keep oxygen high without turning the aquarium into a harsh torrent. Warmer water holds less oxygen, so surface movement and regular water changes are important. Keep ammonia and nitrite at zero, and avoid sudden swings in temperature or pH.

• Use a mature aquarium with stable biological filtration.
• Keep a shoal of at least six Parkinson's Rainbowfish.
• Leave open midwater swimming space.
• Use a secure lid to reduce jumping risk.
• Maintain clean, oxygen-rich water with steady weekly care.

Feeding

Parkinson's Rainbowfish are omnivores and usually feed confidently once settled. Use quality flake, micro-pellets or small granules as the everyday base, then add frozen daphnia, mosquito larvae, brine shrimp or bloodworm as variety. Vegetable-rich flakes and occasional duckweed grazing can also be useful, matching their natural habit of taking small foods from the water column and around plants.

Feed small portions that are eaten quickly. A varied diet, clean water and a settled shoal are the best way to bring out the orange colour in mature males.

Tank mates

This is a peaceful community fish, but it is fast, active and bold at feeding time. Choose companions that enjoy similar water and will not be stressed by constant midwater movement. Good options can include other suitably sized rainbowfish, peaceful barbs, larger tetras, danios, Corydoras that suit the same temperature range and calm dwarf cichlids in large enough aquariums.

Compare Lake Kurumoi Rainbowfish, Banded Rainbowfish and Neon Dwarf Rainbowfish when exploring related species. Check each species' adult size and temperature needs before planning a mixed display.

Sexing and breeding

Mature males are deeper-bodied and much more colourful, often showing stronger orange markings and more extended fins. Females are generally slimmer and more silver-blue. As with many rainbowfish, breeding is possible in mature, stable aquariums, but a separate spawning setup gives better control. Use fine-leaved plants or spawning mops, condition adults with varied foods, then move eggs or mops away from adults if you want to raise fry.

Eggs and fry need clean water and very small first foods. Treat breeding as a planned project rather than something to leave unmanaged in a community tank.

Ordering from Tropical Fish Co

Eligible live-fish orders are supported by our Live Arrival Guarantee when the policy conditions are followed. Read the delivery and live-arrival information before ordering, and have a cycled, covered aquarium ready for a shoal of active rainbowfish.

Acclimate slowly on arrival, keep lights low for the first few hours and avoid heavy feeding on day one. If you are unsure whether your tank is large enough or whether your water suits this species, ask before ordering so the fish has the best possible start.