They're not the fastest growing cichlid. My Alti's grew really fast up to about 3-4" then the growth rate slows down. They will get near a foot long plus some really nice trailers. Geophagus Brasiliensis is the largest of the Geos. They are more 'thick' like most of your CA cichlids.
i was told it was a baby redhead, but am hoping it is an altifrons because i want a larger size geo. there was also a nice wild 5" redhead and bout 2-3 other species of geo there, not shure which though.