Van Heurn's rainbowfish

Melanotaenia vanheurni

Also known as Vanheurni rainbowfish

FreshwaterFish

Care at a glance

Temperature: 73–82°F (23–28°C)
pH: 6.5–7.8
Adult size: 7.3 in (18.5 cm)
Minimum tank: 66 gal (250 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Rare
Origin: Idenburg River system, Mamberamo basin, Papua, Indonesia
Family: Melanotaeniidae

Overview

One of the largest rainbowfishes, this is a big-river fish that needs the longest tank you can give it and some current to swim against, kept in a school of six or more. It is peaceful but a strong, fast swimmer, so it belongs with other large, sturdy, calm fish rather than small or delicate ones. Feed hearty portions of a varied diet: larger granules and pellets, frozen and live bloodworm, and other meaty foods. Plan on at least 250 liters, favoring a long tank with real swimming length and flow.

In the wild

Van Heurn's rainbowfish comes from tributaries of the vast Mamberamo basin in northern Papua, including the Idenburg, now called the Taritatu, a system of big, flowing rivers. Give it a large tank with real current, 23 to 28 degrees Celsius, and soft to moderately hard water around neutral, a pH of 6.5 to 7.8, with open swimming space and a sandy bottom.

Good to know

Melanotaenia vanheurni, family Melanotaeniidae, was described by Weber and Beaufort in 1922 and reaches about 18.5 centimeters, among the largest rainbowfishes known, built long and torpedo-shaped for life in big rivers. Breeding is of medium difficulty, the fish scattering adhesive eggs onto plants or mops, though a group needs plenty of room to spawn.

Did you know

At close to twenty centimeters it is one of the biggest of all rainbowfishes, a torpedo-shaped giant from the remote Mamberamo basin, whose river system stayed largely roadless for a century after the fish was named.

Tank mates

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