Your best bet is to look at species photos on the internet yourself because you know what the fish looks like best.
it is going to be a Haplochromis, and there are only a few species which it could be. try looking at these species profiles: http://www.malawimayhem.com
there are a few there that come close but its hard to tell because of the pictures and the fact that this fish could be a female (in which case many look similar) or a male that hasn't full colored up yet.