Melanotaenia lacustris, sometimes called the Lake Kutubu rainbowfish, is a popular species of mid-sized rainbow from Papua New Guinea. Their care and disposition is about the same as most rainbows of their size; they are peaceful but boisterous schoolers that mix well with most other peaceful fishes but may intimidate particularly shy tankmates. Like many rainbowfish, they are usually not available as brightly-coloured adults; instead, you usually see the drab, greenish-gray babies. While they are a bit of an excercise in patience, when well-fed and cared for, they develop into one of the brightest and most stunning freshwater fish known. Adults are turqoise-blue colour, and males display an intense yellow forehead stripe when fighting or trying to impress females.
These are babies, around 1" long. Their colour has a long way to go, but they're growing quickly!