I agree, it is Pelmatochromis buettikoferi. I picked up some myself at OCA from a guy who was selling breeding age youngsters out of his room. I had a pair form out of the five I kept, and I gave 5 to a friend, who has also had a pair form and spawn. I've heard a lot of people talk about how aggressive they are, but mine have only been moderately so when spawning. Sexual characteristics are not extreme, and require close observation to determine.
Here's a shot of my male when I first got him, fins are rough because the salvini in the tank took a slight dislike to him. (Sal went bye-bye for being a wife killer.)
Here's the pair just before they spawned, female left and below.
There are two kinds of error: blind credulity and piecemeal criticism. Sound skepticism is the necessary condition for good discernment; but piecemeal criticism is an error. - Egyptian proverb