Mariah, sometimes the best time to look at the anal fin is while you are feeding them, they are a little more relaxed and will unclamp their finds better.
Here's a few picks that may help you see the difference....
Female....
http://i4.photobucket.com/albums/y14...tle/female.jpg
Male.......
http://i4.photobucket.com/albums/y14...ettle/male.jpg
male showing aim.......
http://i4.photobucket.com/albums/y14...squitofish.jpg
Comparison of the two.........
http://i4.photobucket.com/albums/y14...le/compare.jpg