is the fish scratching or doing anything out of the ordinary???
if it isn't I would probably go hypo if anything.... as it is a slow process to setup and if the ich isn't that bad then it should be ok. hypo is a bit easier on the fish rather than copper..... but I personally do copper though..... I like to make sure those suckers are dead
also if its in the dt... youll probably find that the ich is in the dt whether the morish idol is in qt or not.
ich needs to host fish to survive.... if you want to kill the ich in the dt... you've pretty much got to remove all fish from dp for 6-8 weeks.
the issue with doing hypo in the DT is that it may kill your BB in there.....
so ich generally can survive without a host for 6-8 weeks.
that why if you remove the fish from the DT and leave it empty for 6-8weeks then the ich will die out on its own with no additives