Red platy and Black mollies pregnancy!? HELP NEEDED

[Matt1992]

Hi, I've bought an aquarium and fishes a few weeks ago and I'm not sure if my black mollies and red platy are pregnant or just fat. Especially one red platy is getting bigger and start hiding.

 

[JemZ]

The platy looks pregnant to me, but I'm not sure about the mollies since I don't know a lot about them.