Mollies dead within hours

[Dolphins18]

First off that marine velvet wouldn't transfer from freshwater to saltwater.
That is why they call it marine velvet not freshwater velvet.
Secondly, mollies die super quick and 8/10 wont survive the acclimation. There isn't much difference between a 2 hour acclimation and a 3 day with these things, seems to be luck of the draw.
No doubt acclimation. If one dies after like a week of being put in the saltwater, then I would worry.
I have found if you pick up the pregnant mollies and acclimate them, they often pop during the transition, and if you separate the babies from the parents the babies almost always make it, no idea why, maybe cause they were born in salt.

 

[Robert Binz]

so i decided to acclimaye mollies to my tank to let them graze on algae and it didn't go well. Within 5 hours 2 of them are dead and covered in white spots before they died. Could disease kick in and kill these fish that quickly or did they just not adjust too well?

it goes against the common wisdom but I don’t think mollies survive long in 35 ppt salinity. Mine slowly died off but the clownfish were happy as could be

 

[Spicoli]

I've successfully acclimated mollies and have them to this day in DT. The orange sailfins seem to do best with the conversion. Black ones died at a higher percentage for me. I also have a Harlequin Mollie that made it. They breed like crazy and do a good job filtering small food particles and picking algae. You find the babies in your filter socks.

 

[Jay Hemdal]

I've successfully acclimated mollies and have them to this day in DT. The orange sailfins seem to do best with the conversion. Black ones died at a higher percentage for me. I also have a Harlequin Mollie that made it. They breed like crazy and do a good job filtering small food particles and picking algae. You find the babies in your filter socks.

Yes, sailfin mollies are a different species, and they always adapt better to saltwater. There are some species of molly that are really just freshwater species. Trouble is, these are all raised in Florida fish farms and lots of hybridization takes place to "set" new strains, so the salt tolerance of any type of molly that you buy now days is a bit of a guess.

Jay