I was told by my LFS
garlic just boosts the imune system of the fish not cure ich. But he did say when you come to do another water change do a bigger one and reduce the salinity alittle as the parsites dont do as well in low salt water.There salinity in there tanks are at 1.015 he said this way the fish has a better chance of fighting it off. He told me not to use any treatments as this will kill everything in you tank from bacterer to invertabrates.
I said what about containing the fish he said not to bother as this just stresses the fish even more.He said your just better off leaving him alone feed him well and keep an eye on him he said in time the fish will fight it off him self,and i have to say he is right as my yellow tang is looking alot better already.
Im giving him Nori,frozen brineshimp with garlic and a few flakes everyday.