They do BETTER in marine then fresh water. I bought a female and male put the bag in the tank for a bit to equalize tank and bag temperature. I then opened the bag took out half the water an filled the bag with tank water. After about 30 minutes I emptied most of the bag and refilled with tank water. After about another thirty minutes put the fish in the tank. That is what I do for all my fish , snails, shrimp etc. etc. etc. Drip = BOGUS ! 8 hours ???
After a year the Male is still going even though he is CONSTANTLY harassed by a pair of fire clowns ( NEVER EVER BUY FIRE CLOWNS !). The fire clowns killed the female after a month and constantly bite the mollies tale to the point where almost the complete tail is gone. The Mollie regrows the tail in a mater of a few days week and the game starts all over.