i know there may not be an easy way to distinguish them apart but i have finally begun moving my last surviving angel in to the 55g. I am looking at getting a few more just to see if they will pair up with the one i have. i just would like a way to determine if the big one i have is a male or female, she's a bit bigger than a 1/2 dollar body size. I know the best bet would be to buy a few more and try and let them pair up but if the bigger ones are easier the sex maybe i just get a bigger one, just let me know guys?