Pseudotropheus demasoni is a species of cichlid endemic to Lake Malawi where it is only known from the Pombo Rocks in Tanzanian waters. This species can potentially reach a maximum length of 10 centimetres (3.9 in) SL. It is now commonly found in the aquarium trade.
The male of this species has dark blue or black vertical stripes with alternating lighter stripes of light blue to white. The male Demasoni Cichlid also displays the typical spots on the anal fin, and is considerably larger than the female. The female of this species are very indifferent from the males although they tend to be smaller in size, and may also lack the spots on the anal fin. When under stressful conditions, whether in the wild or in captivity, their color lightens drastically and they hide in a considerable safe region until they feel safe. This species is highly aggressive for its size.