This is still a very young fish. It is a male just beginning to show adult coloration. Unfortunately I am unable to tell with certainty the exact species as there are a few cichlids that I have seen this coloration in at the beginning of sexual maturity. Some of the solid colored Paralabidochromis such as sp. "fire" and many of the Xystichromis like phytophagus and sp. "day glow" also go through this body morph/color phase when young. Give him a couple more months to fill out and we can probably take a more accurate guess.