i thought with most biological cleaner for ich, like wrasse and shrimp they can't get too deep under the ailing fish to get to the ich that's burrowed under its scales?
I've read the same thing about wrasses and dragonets with the thick mucus they secrete makes them less vulnerable to the ich parasite. Just from observing the animals the hippo and swallowtail angels got it worst, but are looking really good. I saw some spots on the exquisite wrasse, and orange back briefly. Anthias, pygmy angels, blenny, clowns, etc. all look good also.