My female molly has looked intermittently pregnant for the last two or three weeks - round and fat one day, slimmer the next, etc. I don't know if she's pregnant at all. I've heard that silver lyretail molly males are infertile, and that's the only male molly in the tank. I know guppies can breed with mollies, but since there are several female guppies, it's not likely that they would go after the molly. I am sure my swordtail female is pregnant, but she's not as fat in proportion to her length as the platys get, so I'm not sure when she'll drop. Swordtails tend to be slimmer than platys when not pregnant, so she may never be that fat in proportion. I'm just watching and waiting. I don't have anyplace to separate her, or anyplace for her fry to grow up, since I already have about 150 fry, total, so unless some make it in the main tank, it really doesn't matter this time. Maybe after the current fry grow up and go to the pet store I'll raise some of her fry.
I did take a bunch of pictures of all my tanks Monday evening, and if I have time later I will post them. I also have videos, but since I'm not on youtube I can't post those here. If you'd like to check out some pictures of my current fry when they were tiny, as well as some older pictures and videos of various tanks (and my cat), you could see them at Pictures by amthyst123 - Photobucket