Guppys, Platys, Swordtails & Mollys are pregnant 99% of the time so if yours was in a tank with a male at any stage (even as half-grown fry), she will be pregnant. These species can store semen from past matings so don't even need to mate every time to have fertilized embyros start forming. If she looks pregnant, she almost definately is. They usually give birth every 30 days so the very most you'll have to wait is 30 days. Probably less if she is almost ready to drop. There's another thread here about the shape of the female's tummy turning from rounded, to a boxy, flat-bottomed look. The photo in that thread could help you too. Just check every morning and evening for babys in the tank. You might want to put in some thick weed for the babies to hide in if you have other tank mates that might eat them or you can put the female in a breeder net so that she and her babies are safe from other fish. You'll have to keep an eye on the mother too because they can sometimes decide to snack on their babies after a day or two as well, though not usually.
). I just got her from the pet store yesterday, and i wanted to know if she looked pregnant, or if she is just fat. I'll add a pic below. Thanks!
