My lfs keeps mollies as well as guppies in saltwater for those that want to feed live fish to certain marine fish......You just can not dump in mollies or guppies into salt water and expect them to live, but slowly acclimated and they do just fine, evewn to the point of breeding.......Mollies were my first saltwater fish and I kept a tank of them which bred like rabbits, for over two years. I still have a few in a 10 gal tank I use for a QT tank on occasion, and snatch their young fry up to feed to my chalk basslet..........as I do not want to raise them anymore......so I just use their offspring to feed my basslet. When the adults die, that will be the end of the mollies for me.