Cichlids can catch up over time... the fast growers max out earlier while the slower growers maintain a steady slower growth over time. I've observed slower growing stunted specimens go through growth spurts and catch up, later on. For example my largest male Festae slowed at about 9" and the other male that was half his size caught up, quickly when introduced to his mate in a seperate tank. A lot of it is down to conditions and order of dominance. Also fish in pet shops that haven't sold for quite some time appear to be stunted yet as soon as they are introduced to your aquarium them grow at a very fast rate and catch up with what size they should have been if in the ideal conditions from the outset.