Aulonocara sp. "Stuartgranti Maleri" (Chipoka) aka "Sunshine Peacock"
Based on the pic at MonsterFishKeepers. The tail markings (blue on yellow) rule out my initial guess, and point me towards the Chipoka. When it fully colors up, they're beautiful.
Very peaceful (as far as Africans go anyway), typical Malawi water specs, Needs animal protein unlike Malawi Mbuna so careful with the diet if your tank is mixed. The males don't color up until about 2 years of age, and your's is starting to color. If you have more than one male, expect one to become far more colorful than the other. If at all possible, look for 2 or 3 females for him. That will give him a bit more courage to fend off any other more aggressive tankmates.
Great find and great fish!