Lake Tebera Rainbowfish

About

This is the yellow rainbowfish. A mature male is gold to greenish gold with one blue-black line running the length of the flank and red or yellow unpaired fins; in spawning dress he adds a blue-white stripe from the first dorsal over the nape to the tip of the snout while the whole head darkens to near black. It lives only in the Lake Tebera basin of the Papua New Guinean highlands, a chain of interconnected ponds, swamps and springs about 10 km by 2 km sitting at 793 m among mountains of 1200-1500 m. The address matters: that water is alkaline and mineral-rich, and the species will not do well in soft, acidic conditions — which sets it apart from most of the tetras it is sold beside. Shops sell drab silver juveniles of 3-4 cm; the adult is a deep-bodied 10-12 cm fish, and the gold arrives over the first year, not in the bag. The IUCN listed it Vulnerable in December 2019.

Care

Six or more in a tank of at least 90 cm and 150 L, in alkaline medium-hard water at 20-26 °C with slow flow, dense planting at the sides and open lanes down the middle for the males to display in. Fit a tight lid — rainbowfish jump. Soft, acidic water is the one setup this fish should not go into, and full colour takes a year or more, so judge it by adults in a mature tank rather than by the juveniles in the shop.

Diet

A micropredator on zooplankton, insects and plant matter that eats anything offered in captivity. Dry food daily, frozen or live bloodworm, daphnia and brine shrimp two or three times a week for colour, and the occasional green. Keep the pieces small — the mouth is narrow — and do not house it with dwarf shrimp or fry.

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.

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Frequently asked questions

What tank size does a Lake Tebera Rainbowfish need?

A Lake Tebera Rainbowfish needs an aquarium of at least 150 litres (39.6 US gallons) with a footprint at least 90 cm (35.4 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Lake Tebera Rainbowfish need?

Lake Tebera Rainbowfish does best at 20–26 °C (68–78.8 °F), pH 7–8.2 and a general hardness of 8–18 °dGH.

What group size does a Lake Tebera Rainbowfish need?

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

Is the Lake Tebera Rainbowfish suitable for beginners?

Lake Tebera 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

• Seriously Fish — Melanotaenia herbertaxelrodi (Lake Tebera Rainbowfish)
• FishBase — Melanotaenia herbertaxelrodi, Lake Tebera rainbowfish
• AquaInfo — Melanotaenia herbertaxelrodi (text by Adrian R. Tappin, Home of the Rainbowfish)
• Aquadiction — Lake Tebera Rainbowfish, Melanotaenia herbertaxelrodi
• Aquarium Co-Op — Top 10 Amazing Rainbowfish for Your Next Freshwater Aquarium