You know, I don't think I really care if they are stunted, now that you mention it. The juvies eat like crazy and grow like crazy. The parents breed way too fast, but I found a wild card to keep the populations at bay-harder water. They spawned in those last pics and all the eggs were duds. To make them hatch all I do is add a water softener pillow to the setup. Thus, giving them longer healing times.
I do alot reasearch on this stuff (obviously) and it seems most of the time that show fish aren't usually the breeders, besides, growth stunts aren't a product of genes, they are the product of enviornment (yes I know there are exceptions). And, really, 3.5 inch just takes up less space than say 8 inch. Something to think about.
Just fyi, they are the only stunted fish I have, I don't want to sound like a discus slumlord.