It is a damsel, maybe a chromis? I would have to look, but there are many different species of chromis that get big are semi aggressive and lose all or most of the juvi color pattern. My thoughts are not sure, the mouth and curve of the face is wrong for most of the chromis I can think of right now. I will take a look but the other species I was thinking it reminded me of is the adult of the neon velvet damsel, has the right shape and as adults they lose all of the blue and white.