Boeseman's rainbowfish (Melanotaenia boesemani) is a species of fish in the Melanotaeniidae family. It is also known as the Boesemani rainbowfish. It is endemic to the Ayamaru Lakes and their tributaries in a mountainous region of the Bird's Head Peninsula, West Papua, Indonesia.
It is also available in the aquarium hobby, where it is prized for its excellent colors and peaceful demeanor. The colour pattern is completely different from most other forms of rainbowfish, as it has a half orange-red rear and a bluish-grey or purple front which in some specimens is almost defined perfectly. Melantotaenia boesemani will often grow to lengths that exceed 10 cm if given the right food and water conditions. They are kept best in groups due to their community and friendly nature and can be easily kept with many different species of fish, including some tetras. They are a relatively hardy fish that prefer weakly alkaline pH conditions. Good tank mates include other rainbowfish, barbs, and loaches.