Out of ideas.

[Zoaelite]

What sort of frozen foods are you feeding? The problem with Ich is that it really only effects fish with a compromised mucous coating. Once the parasite and any other extraneous factors cause the fish to stop eating it's very tough to turn it around. Have you tried soaking regular nori in selcon? If that doesn't work I would try brine shrimp or some other frozen.

Also put the rock from your sump back in the main tank, fish will be less stressed with more hiding places. Plus if there not eating your food the extra live rock makes for good snacking.
Levi