Male or Female?

This is the web site that helped me figure out which one is which

http://www.fishforever.co.uk/livebearers.html

I hope this helps

not that hard really.. just look at the anal fin.. females have a fan-shaped anal fin, while males have a gonopodium which looks like a pointed rod :dive2:

It can be hard to sex them if the tank they are living in isn't well kept. I have seen many a platy in Petco. that has dorsal and anal fins tucked in constantly as well as til partially collapsed. General rule of thumb: don't buy a platy unless you can sex it. If you can't, it is possible sick or on its way to being sick. If you go to a store that has nice, healthy platies with extended fins, you will also probably be able to find someone there who knows how to sex them if you can't tell.

But to make it simple:

Female:
http://images.clix.pt/canais/arcadenoe/races/4/platy.jpg
(Note the triangular fin in the rear on the bottom)

Male:
http://www.zooroco.ch/images/Fische/platy-01057.jpg
(Note the tubular fin in the same place)