Yes a pair that has been together long enough breeding non stop from my exerience will stop breeding or atleast slow down greatly. our two year old male is 5", he grew up in a 20 then to a 55, then to a 125g with his mate. Our female who was his same age and grew up with him only grew to about 3". They did however eventually stop breeding. I have seen convict raised in huge pond like wells and they are about 6-7"