I have heard breeding some cichlids stunts growth. I have about a 4 inch male green terror and a small 3 inch female. Well she is about to lay eggs and they are definently a pair. Will the breeding stop the growth of either one of these fish.
It simply takes energy away from growing and puts it toward the production of eggs and guarding the nest/fry.
Will your fish grow slower because they're breeding? Yes. More so the female but it will slow down the male as well. Will they grow normally when not breeding? Yes. It's not like one spawn and they're stuck at that size forever.