Ryan :

I don't think the feed you are using would have an effect on coloration under your circumstances. The feed I use, as best I understand, is like yours wrt not having fish meal or animal by products although it is not 42 %.

Bruce it is good to know that with all the BG I have observed and read about including your great articles I can tell male from female about as well as flipping a coin (60% of the time). :p Just kidding. As you , Bill and Ryan note the obvious males and females (probably 65% of the population)are no problem. It is the young ones and the sneekers and cuckholders that are hard to id. I am not trying a male only pond so the if in doubt hold them out process will not help rid the pond of lesser fish and sneekers and cuckholders. Thanks for the help. Any more tips ? \:\)

Another question about fish 2. It like the others was stocked at the same time. It is just as big as the other males of the same age and is in good condition. Some females in this pond are also that big. Why would it not have dominate breeding male colors and ear flap? With those colors any chance its breeding strategy is that of a female impersonator ?