Just my opinion, but if he's in QT that long with no visible signs of infection then I wouldn't worry about any kind of treatment. Also, wrasses typically are not susceptible to ich and copper treatment may do more harm than good. Most wrasse keepers will use Prazi to "de-worm" their wrasses, but again if he's doing fine after 2 months in QT then why treat him? Now, you can take all that with a grain of salt if you like because I personally don't believe in prophylactically treating fish, but in the all years I've been doing this, I've never had a wrasse show any sign of disease (except for a pintail that developed the weird neuro symptoms that nobody really has an explanation for).