if it was male the extension of the fins would already be there....my 3inch male has way longer fins than she does.....also, she is more round in shape, doesnt have the intense coloring that a male has, and her orange bands on her fins are not as thick as male's would be..........watch this video of my male, he is only 3inches....
http://www.youtube.com/watch?v=VIj_NFsRaiI
http://www.youtube.com/watch?v=VIj_NFsRaiI