Really nice fish. Cant say I have had one like it. I dont readily recognize the species but someone else may. However its features/proportions look like some type of Chindongo or possibly Pseudotropheus to me. Some more info might help narrow it down. Where did you get it? How big is it? How old is it or how long have you had it?
The thin barring and fin coloration looks like a Cynotilapia sp. 'hara' Gallireya Reef. Maybe an immature or subdominant male hara. I never kept hara so its just a guess on my part. Hopefully somebody will chime that has experience with hara.