Ajamaru Lakes rainbowfish

Melanotaenia ajamaruensis

Also known as Ajamaru rainbowfish, Ajamaruensis rainbow

FreshwaterFish

Ajamaru Lakes rainbowfish (Melanotaenia ajamaruensis) — The Wet Spot Tropical Fish · Used with permission

Care at a glance

Temperature: 75–84°F (24–29°C)
pH: 6.5–8.0
Adult size: 4.3 in (11 cm)
Minimum tank: 42 gal (160 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Rare
Origin: Ajamaru Lakes region, Bird's Head Peninsula, West Papua, Indonesia
Family: Melanotaeniidae

Overview

Keep this active midwater rainbowfish in a group of at least six, since a lone fish stays pale and skittish while a school settles and colors up, and males show best when they have rivals to display to. It is peaceful and mixes well with other calm, similarly sized community fish that will not nip its fins or outcompete it for food. Feed a varied diet of quality flake and small granules with regular frozen or live foods such as bloodworm, daphnia, and brine shrimp, plus some algae-based food. Give it room to swim, a tank of around 160 liters or larger suits a starter school.

In the wild

The Ajamaru Lakes rainbowfish comes from the Ajamaru plateau on the Bird's Head Peninsula of West Papua, a karst region of clear, mineral-rich water over limestone. Recreate that with neutral to alkaline, moderately hard water at a pH of 6.5 to 8.0 and a temperature of 24 to 29 degrees Celsius. A planted tank with open swimming lanes, some water movement, and bright light to trigger morning display suits it well.

Good to know

A member of the rainbowfish family Melanotaeniidae, Melanotaenia ajamaruensis was described by Allen and Cross in 1980 and grows to about 11 centimeters. Like other rainbowfishes it is an egg-scatterer of medium breeding difficulty: a conditioned group deposits adhesive eggs onto fine-leaved plants or a spawning mop over several days, and the main challenge is rearing the tiny fry on very fine foods. It shares its lake plateau with the well known Boeseman's rainbowfish.

Did you know

Science lost this fish for decades. After it was collected in the 1950s it went unrecorded for many years and was feared gone, until fieldwork around 2007 found it surviving in the Ajamaru catchment, and most aquarium stock traces back to that rediscovery.

Tank mates

Ajamaru Lakes rainbowfish is a peaceful, schooling species that keeps to the middle. These picks match on water type, temperature, pH, size and temperament.