Is this marine Ich?

Hey guys,

Is this marine ich or something else and what is the best way to go ahead and treat? Other fish in the tank look OK apart from the Regal Tang, with a small sign of the same.

I have corals and inverts in the tank so I guess this rules out any copper based treatment.

I have a QT tank, which has not been running for months. Should I set this up and if so whats the best way to do it.

Thanks in advance, Michael

Thats deff the way Im heading. Have a small tank that would do one or two fish, so Im gonna get my hands on a larger tank tomorrow for QT so that I can treat all the fish to stop any spread.