thats why i breed in pairs .... I want x to spawn with x... not y... so i keep y out of the mix. saves me from having to guess on things, and gives me a 100% sure who the father and mother are. also I can count on colors that I want to get out off the spawning, and see if things breed true or not... you cant do that 100 % in a group spawning... most Ill do is add one extra male to get the calling going heavy then pull him... if it was a slow pair.