Molly/Platy?

[SDragon]

A couple of days ago I bought 4 ffish from Walmart. In the tank they had Sailfin Mollies, Lyretail Mollies, Mollies, and Platies. My brother and I bought one Lyretail Molly and four smaller ones. The prob is we can not tell if we have mollies or platies. There is one all black one, one black with silver on its stomach and two black and yellow ones. I will ret and post pics later. But does anyone know how to tell Mollies and Platies apart? Or know which ones these might be? THank YOu.

[ChoclateBetta]

http://www.theaquariumwiki.com/Mollies http://www.theaquariumwiki.com/Platy which are they similar to also don't mollies have flatter backs.