Your molly is probably pregnant...I am not sure about the guppy. It might be pregnant or it might just be healthy and fat. Is there a gravid spot on the guppy?
There is a gravid spot on the guppy...so most likely she is. I've noticed that the molly's stomach continue to grow so I think she is pregnant. She is my first female molly, never had molly fry ... only guppy fry.