I am really having a hard time getting a good picture of this fish! He is really active, and hard to get a still enough shot of him; always in constant motion. But here goes yet another try.
It definitely is an Aulonocara. The Sciaenochromis fryeri has a blue fringe on its dorsal fin. And the Otopharynx lithobates has an orange fringe on its dorsal fin To where your has a very distinct white on its dorsal fin. And the O. Lithobates tends to have darker blue spots on its flanks (the side of the fish right beyond the pectoral fin). And the O. also has an orange on its top starting from the point of the mouth to the tip if its dorsal....