New fish, quarantine and copper

[George]

I am also voting for tank transfer method (TTM) for eradicating marine ich. But the method requires a little bit of planning which includes extra hardware and such.
If you don't have the necessary hardware for TTM, cupramine is a fine choice for those fish since they are tough fish. make sure they are eating well for a week before the treatment. Ramping up the copper level to therapeutic level slowly over a few days.
Good luck!