Fish disease transferring FW TO SALT??

[ReefGuy1234]

I’be had this molly that I have been waiting to get over to salt but I’m ready now. However he has some cloudy thing on his fin I haven’t been able to id. It’s probably something fungal or bacterial. If I acclimate him to saltwater will what ever he has died off?

Heres a picture - not the best example

 

[ReefGuy1234]

Never mind look at some old threads and found that if its bacterial then it would not live but I think its fungal so Im not sure about that.