Melanotaenia boesemani, or Bosman's Rainbowfish.  I believe that I have two female Boseman's Rainbowfish, and that because of this,  their color has never developed to the extent I expected.  See this web page for a look at their true potential. When fully "colored up" the males of this species are spectacular to look at.  Boseman's Rainbowfish exist in the wild only in Lakes Ayamaru, Hain and Aitinjo and their tributaries in the center of the Vogelkop Peninsula, Irian Jaya.  They prefer water temperatures of between 77 and 82 degrees Fahrenheit.  Boseman's Rainbowfish need a large tank with plenty of swimming area, and will eat just about anything they are offered.  They are peaceful, active, schooling fish that are non-destructive to plants.  They can grow up to 5.5 inches in length.