100% NOT curviceps. It's lacking the 3 facial stripes that make up the Laetacara genus. I don't believe it to be an acara at all.
It's most likely one of the northern port cichlid clade, without knowing it's location it might be impossible to tell which one though. I'd vote for either the black port (Cichlasoma bimaculatum) or Amazon port (Cichlasoma amazonarum) since they are the two most commonly imported of these Cichlasomines.