So I have these 2 stingrays my marble is fully mature huge c laspers his disk is around 12 inches width. And my female is a hybrid motoro not positive what she is but she is around 15 inches width I have added the male to my 500 gallon aquarium a month ago and he has not shown any interest. No Bite marks on female at all. Water parameters are. Ammonia 0. Nitrate 40. Ph 7. Any have any clue why they won't breed