hiya, well, if you can take a pic of them, and upload that, i will be able to tell you.
the main way i tell is the top fin, the males have longer and pointy dorsal fins, but also, depending on how old they are, their feelers are a stronger colour.
if you wud like me to have a go at telling you which is which, upload a pic, and i can try. but im sure if you upload a pic, there will be alot more ppl who can help u to tell them apart.