Parkinson's Rainbowfish

About

One of the largest rainbowfish in the hobby: silver-blue with narrow orange lines between the scale rows and, on a mature male, an irregular blotch of brilliant orange or red spilling across the whole rear half of the body, which is why the fish looks half-dipped in paint. It reaches 15 cm, with most fish settling just under 12 cm; the long dorsal and anal fins of old males often look deliberately ragged, and that is normal, not damage. It is a lowland stream fish from the south coast of eastern Papua New Guinea and it wants real warmth — 26-30 °C, which is hotter than most community tanks and hotter than the highland rainbowfish it is sold beside. Juveniles are grey and forgettable, so this is a species people walk past in the shop and then admire in someone else's tank two years later. A naturally occurring yellow morph exists but is rarely exported. The IUCN listed it Near Threatened in 2019.

Care

A 120 cm tank of 180 L or more, six or more fish with extra females, and 26-30 °C — this species genuinely wants the warm end, and warm water holds less oxygen, so strong filtration and surface movement matter more here than in a cooler tank. Alkaline, medium-hard water suits it best, though it tolerates a wide range. Keep the lid tight. Males spar over females without doing damage, and full colour takes a year or two.

Diet

Omnivore taking flake, green flake, micropellets and small frozen foods; frozen or live mosquito larvae, daphnia and brine shrimp bring the orange up. It will browse duckweed. Feed several small meals a day to an active shoal.

Telling males from females

What works for this species, most reliable first.

• Colour and patternStrong · from about 6 months, and only on a settled fish

  In rainbowfish, killifish and several barbs the male carries the colour — deeper and more saturated, intensifying further when he displays.

Also in these lists

Similar species

Same category and the closest water parameters — if this species isn't quite it, start here.

Sold in Lithuania

These Lithuanian shops listed this species in their public catalogue (checked August 8, 2026). Stock moves — ask before you travel.

These links are unpaid: we get nothing for them and ask for nothing.

Frequently asked questions

What tank size does a Parkinson's Rainbowfish need?

A Parkinson's Rainbowfish needs an aquarium of at least 180 litres (47.6 US gallons) with a footprint at least 120 cm (47.2 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Parkinson's Rainbowfish need?

Parkinson's Rainbowfish does best at 24–30 °C (75.2–86 °F), pH 6.5–8.2 and a general hardness of 8–20 °dGH.

What group size does a Parkinson's Rainbowfish need?

Parkinson's Rainbowfish is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.

Is the Parkinson's Rainbowfish suitable for beginners?

Parkinson's Rainbowfish sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

• FishBase — Melanotaenia parkinsoni, Parkinson's rainbowfish
• Maidenhead Aquatics (fishkeeper.co.uk) — Parkinson's Rainbowfish, Melanotaenia parkinsoni
• AquaInfo — Melanotaenia parkinsoni, Parkinsons Regenboogvis (text by Adrian R. Tappin, Home of the Rainbowfish)
• Aquadiction — Parkinsons Rainbowfish, Melanotaenia parkinsoni
• Aquarium Co-Op — Top 10 Amazing Rainbowfish for Your Next Freshwater Aquarium