You are going to have to get him pods unfortunately. He may not make it. Not all of them can be trained onto frozen foods. You can order some off of this site and a lot of LFS sell live pods by the bottle. You should do it soon though.
They are resistant... not immune. Their slime coat does protect them a nice bit, but their gills are just as vulnerable as the rest. That makes them "quiet" ich carriers. You may never see it ON them because it's actually hidden in their gills.
