there are two easy ways to tell the difference between males and females
first off
Male
Female
Males have much longer flowing fins than females, they also are more vibrant in their colour.
Second...the fins on the underside of the fish are different...i find this bit hard to explain...so i use pics
just look at the hightlighted areas of the fish and compare them to yours.
the males are usually the 1's with the bigger tail fins and more colourfull and they have an extra "fin" on there belly that looks like a stick, the females will have a dark spot around there butthole, thats where the babies are kept