Might have to eat my own words re: quarantine

[George]

Sorry to hear about that Brad.
Life cycle of Marine velvet is very similar to marine ich where they can multiply by numbers with day goes by. So you may not see the symptom for days (or weeks) and then bam!
I would suggest giving the fish a freshwater dip after you go them out. And give them a formalin bath after that. After that, put them into a QT and treat any secondary infections.
I hate to be pessimistic but if you see sign of marine velvet, most of time it's too late. Hope for the best and prepare for the worst.
Good luck.