[howdy20012002]

Sorry, but I disagree about not having LR in a quarantine.
ich needs a host to reproduce. without it, it will die.
after feeding on the host, it drops off and it becomes a Trophont.
it will stay in this stage regardless if there is live rock, sand or nothing at all.
it then hatches typically within 6 - 10 and must find a host within 2 days to survive.
not sure what Ken meant by Ich can survive on LR when not on fish.
if no fish host, the ich dies within 48 hours after hatching.
I would highly recommend that you use live rock in your quarantine.
otherwise you could potentially deal with spikes in ammonia and so forth.
Chances are you probably had ICH in your tank from before.
Or the Harlequin had it during the quarantine and you may have missed the signs.
like others have said, I wouldn't stress out too much as ich is in most tanks and will tyically not kill a happy, healthy fish.
trying to catch him will stress the whole tank out which will increase the chances of others starting to show symptoms as well.
just want to clarify that garlic is not a cure, it will just increase the fish likeliness to eat which in turn increases their immune system.
eating fish are typically healthier fish.

good luck