Ammonia presence in a tank stunts growth(that is the origin of the fish grow to their tank size myth), if you are feeding more heavily typically that comes with ammonia levels going up and so people do water changes to keep water pristine, Temps also seem to help dramatically tanks I've raised fry in at 72 degrees vs 82 of the same species have a HUGE disparity in growth rate. I would say a combination of Temp, water changes, and more regular feeding/substantial healthy diet will more that double a fishes growth rate. I've had fish reach sexual maturity 6 months early if reared properly.
Honestly most fish graze more at a younger age so regular feeding is actually better for them, take discus for example. Discus will permanently stunt quite easily if not reared right.
