looks like a young Nimbochromis venustus, from Lake Malawi, Africa. Hope you have a big tank (120g+) as these puppies can get to be 11" or so. The males are beautiful when they mature, the face will turn a metallic blue with a yellow blaze extending from the mouth through the dorsal.
I had one that came with my 55g and I got rid of it pretty quick, they deserve a nice big tank =)