It could be any cichlid but its most likely a tin foil barb. This is an aweful practice by the way it kills lots of fish as they have to be removed from the water while there tatooed.
Its most likely a barb of some sort or if it is a cichlid its probably a parrot cichlid. Please do not buy any tattoed fish though, as it is just wrong. No fish should have to go through such torture just for our sick pleasure.