Lake Kurumoi Rainbowfish

About

Sold in most shops as the sunset dwarf rainbowfish, this is a small, restless Melanotaenia of about 8 cm that comes in two male colour forms from the same lake: one pale lilac to bluish with a black mid-lateral stripe and red fins, the other silver flecked with red and carrying a thin red line between every scale row. Both are drab as juveniles and both take months to arrive. The honest part of its story is the water it came from. Melanotaenia parva is known from a single lake — Kurumoi, at 400 m on the Vogelkop Peninsula of West Papua — whose level has dropped so far that it now sits below its own natural outlet with no visible drainage, and the IUCN assessed the species Critically Endangered in December 2019, with unconfirmed reports suggesting it may already be gone from the wild. The fish in the shop tank is not a wild-caught rarity; it descends from live specimens Heiko Bleher collected in 1999 and is bred commercially. Common on the shelf and critically endangered at home is not a contradiction — it is two different populations, and only one of them is safe.

Care

Six or more in a well-planted tank of at least 80 cm and 90 L, at 24-28 °C, pH 6.5-7.5 and up to about 15 dGH, with clean, well-oxygenated water and weekly changes. Floating plants take the edge off bright lighting. It will not trouble smaller tankmates — the mouth is too narrow to swallow them — but it is fast enough to out-eat slow feeders. Lid on.

Diet

Omnivore. Flake, green flake and micropellets daily, with small frozen or live mosquito larvae, brine shrimp and daphnia several times a week, and spirulina or an algae wafer for the plant side. Small pieces only.

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 Lake Kurumoi Rainbowfish need?

A Lake Kurumoi Rainbowfish needs an aquarium of at least 90 litres (23.8 US gallons) with a footprint at least 80 cm (31.5 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Lake Kurumoi Rainbowfish need?

Lake Kurumoi Rainbowfish does best at 22–29 °C (71.6–84.2 °F), pH 6.5–7.5 and a general hardness of 5–15 °dGH.

What group size does a Lake Kurumoi Rainbowfish need?

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

Is the Lake Kurumoi Rainbowfish suitable for beginners?

Lake Kurumoi 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 parva, Lake Kuromai rainbowfish
• Maidenhead Aquatics (fishkeeper.co.uk) — Sunset Dwarf Rainbowfish, Melanotaenia parva
• AquaInfo — Melanotaenia parva (text by Adrian R. Tappin, Home of the Rainbowfish)
• Aquadiction — Lake Kurumoi Rainbowfish, Melanotaenia parva
• Aquarium Co-Op — Top 10 Amazing Rainbowfish for Your Next Freshwater Aquarium