Boeseman’s Rainbow Fish

When the first specimens of Boeseman’s rainbowfish went on sale in 1983, they caused a sensation. Up until then, fish from New Guinea had hardly been imported, and then there were such miracles of color. Today Boeseman’s rainbowfish swims in many aquariums and has not yet lost any of its attractiveness.


  • Name: Boeseman’s rainbow fish, Melanotaenia boesemani
  • System: Rainbowfish
  • Size: 10-12 cm
  • Origin: Vogelkopf Peninsula, West Papua, New Guinea
  • Attitude: easy
  • Aquarium size: from 300 liters (150cm edge length)
  • pH value: 7-8
  • Water temperature: 22-25 ° C

Interesting facts about Boeseman’s Rainbowfish

Scientific name

Melanotaenia boesemani

Other names



  • Class: Actinopterygii (ray fins)
  • Order: Atheriniformes
  • Family: Melanotaeniidae (rainbow fish)
  • Genus: Melanotaenia
  • Species: Melanotaenia boesemani (Boeseman’s rainbow fish)


These rainbow fish reach a length of about 10 cm in the aquarium. In large aquariums from 400 l, however, it can also be 12 cm or even more.


The males are metallic light bluish in front in normal color, through the middle, there is a faint, vertical, dark stripe and the rear body is orange. The females look like a paler image of the males. During courtship (morning and evening, especially glorious in the morning sun), the colors of the male change. The front part of the body turns steel blue to almost black, the median stripe black, and the rear part bright orange. With some color variants, the rear part of the courtship can also be yellow or bright red.


Boeseman’s rainbowfish comes from the Ajamaruseen in the center of the Vogelkopf Peninsula in western New Guinea (West Papua) and some adjacent rivers and lakes.

Gender differences

The sexes can be recognized on the one hand by the stronger coloration of the males, which already appear at a length of 3 cm. They also have longer, more pointed dorsal and anal fins that reach over the base of the caudal fin. In the case of females, they end well before that. During courtship, a golden-yellow to bluish courtship strip appears on the back of the male (snout to dorsal fin base), which it can switch on and off in a fraction of a second.


Rainbowfish – also this species – are permanent spawners. This means that the females lay some very small eggs every day, which are then directly fertilized by the male. They are very adhesive and hang on the plants or on an extra spawning mop in a separate spawning aquarium. They are very hard and can also be read and placed in a separate small aquarium. After about a week, the very small cubs hatch and immediately need food such as small infusoria or microalgae (Chlorella, Spirulina), but are then easy to raise.

Life expectancy

Boeseman’s rainbowfish can live to be over 10 years old.

Interesting Facts


These rainbow fish are omnivores and will not take any food that is too large. Since they can always find food in the aquarium (algae, also duckweed), they should be given one to two fasting days per week. Young fish, however, have to be fed more often (initially several times, up to about 5 cm in length twice a day).

Group size

Rainbowfish like Boeseman’s rainbowfish only feel at home in a group. Since the males can drive quite strongly, there should always be one to three more females than males. However, it is also possible to keep a squad that only consists of males, as the arguments are always peaceful.

Aquarium size

An aquarium from 300 l is sufficient for a small group of up to ten animals (corresponding to an edge length of 1.50 m). The larger the aquarium, the larger Boeseman’s rainbowfish can become, and in very large aquariums (from 600 l) 15 cm has already been reached.

Pool equipment

Part of the aquarium should be densely planted so that the females can retreat there if the males chase them too hard. Stones and wood are not necessary, but stones do not interfere. Wood, on the other hand, could possibly lower the pH value due to the tannins it contains, which would usually be unfavorable for keeping this fish. The substrate can be any, as Boeseman’s rainbowfish never visits the bottom.

Socialize Boeseman’s rainbowfish

Provided that the tank is large enough, Boeseman’s rainbowfish can be kept with all other peaceful fish. However, they should not be bigger than him, otherwise, he could become shy, withdraw and not show the most beautiful colors. Since it lives in the middle layers of water, fish are particularly suitable for the bottom ground and those that live near the surface.

Required water values

The temperature should be between 22 and 25 ° C, the pH value between 7.0 and 8.0.

Mary Allen

Written by Mary Allen

Hello, I'm Mary! I've cared for many pet species including dogs, cats, guinea pigs, fish, and bearded dragons. I also have ten pets of my own currently. I've written many topics in this space including how-tos, informational articles, care guides, breed guides, and more.

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