Looks like a Kenyi. If it is about 5" probably a in that color a female but could be a male if younger. If Male, he will turn yellow when sexualy matured.

Thank you Kye I been wandering what it was..

Actually i might be wrong. The face doesnt look quite right to be a Kenyi. I will leave it to the pros ;)

Possibly a metriaclima species of some sort but not a kenyi (color and stripe pattern don't match, among other features). Post a full body shot of this fish.