Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Pseudotropheus saulosi - Pseudotropheus saulosi is a species of cichlid endemic to Lake Malawi where it prefers areas with rocky substrates. It comes from an area of the lake called Taiwan Reef and from nowhere else. This species can reach a length of 10 centimetres (3.9 in) TL. The fish are born yellow but as they reach maturity males turn blue with several vertical black bars. Not all males turn and it is possible for some males to remain mixed in with the females in full female dress.
A:
Animal