When I we rear bluegill we can get growth rates that do not occur in nature, especially once the fish get above 6". A problem we have with exceptionally large females we call Big Berthas is many, if not most are "dead heads" . Dead heads have little or no interest in the courting dudes but we have had some spawn when injected with hCG. Maybe problem is related to what is indicated below. The male Bluegill do a song and dance routine that may be more important than we think.