I just picked up 2 male A. Agassizii at Petsmart. They were labeled "Double Red". I couldn't resist giving them a shot after losing my mated male a few months ago. Crossing my fingers!:red_mouth
The fins on males and females are noticeably different also. The dorsal fin on males will usually have the third fin/spike longer than the rest, females will not have that. From what I've have noticed females will also have black in their pelvic fins (fin underneath it's belly) while males will usually be clear or colored. The tails of females are also rounded where as males depending on the species will have different shapes to them, such as Ap. Cacatuoides the males will have small extensions at the tips of their tails. Hope that helps.Any way to tell males besides color?