Boeseman's rainbowfish

Melanotaenia boesemani

Also known as Boesemani rainbowfish

FreshwaterFish

Boeseman's rainbowfish (Melanotaenia boesemani) — H. Zell · CC BY-SA 3.0

Care at a glance

Temperature: 81–86°F (27–30°C)
pH: 7.0–8.0
Adult size: 4.3 in (11 cm)
Minimum tank: 30 gal (115 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Hard
Rarity: Rare
Origin: New Guinea
Family: Melanotaeniidae

Overview

Boeseman's rainbowfish look their best in a group of six or more, ideally with several males so they show off the two-tone blue and orange that mature males develop. They are peaceful midwater swimmers that mix well with other calm fish that enjoy warm, harder water. Good color comes with age, quality food, and bright light, so be patient with young stock that arrives fairly plain. Feed a mix of flake or small pellet, frozen bloodworms, daphnia, and brine shrimp. Plant the edges heavily and keep open swimming space through the middle. Aim for a tank around 115 liters or larger.

In the wild

This species is native to the Ajamaru Lakes and connected streams on the Vogelkop Peninsula of western New Guinea. The lakes are warm, clear, and hard with alkaline water, which is why it wants a pH of about 7 to 8 and a temperature between 27 and 30 degrees Celsius, warmer than many rainbowfish. Recreate that with fine substrate, rock and wood, plenty of plants around the sides, and steady warmth with clean, well-oxygenated water.

Good to know

Melanotaenia boesemani belongs to Melanotaeniidae and grows to around 11 centimeters. Males carry the deep body and split coloring the species is known for, while females stay slimmer and more silvery. It is an egg-scattering spawner that lays a few eggs a day across a long period, attaching them to fine plants or mops with short threads, and offers no parental care. Steady conditions and separating eggs from adults help, but consistent results are difficult, so breeding is rated hard.

Did you know

The fish is named after Marinus Boeseman, the Dutch scientist who described it, and it comes from just a handful of lakes. Heavy collection for the aquarium trade has pressured wild stocks, so most fish sold today are farm bred.