I was just chatting to a colleague at work who has a lovely species only tank full of balloon mollies and last year one of his got a small prolapse which self resolved within 24 hours, but he says his other 3 that had uterine prolapse died - he removed all three from main tank and still isn't sure if it was the right decision.
I have 5 lye tail mollies and definitely 3, maybe even 4 are pregnant - I will keep an eye out for things like this! The male molly is definitely working overtime by the look of the ladies :O