Does anyone have any suggestions regarding this? I have an LFS and keep many angels in many different sizes, up to 15". They are kept in many different tanks, that have been established for 5+ years with lots of live rock, and some with skimmers and some without. almost all other angles that have this heal up, except for the imperator. Many of my customers try to return them after a few months or so. We get them from bali, to christmas island to sri lanka. The ones from bali seem to be the better ones. We currently have 5 imp in the store, 1 is perfect, 2 have slight HiH on one side, and 2 have it pretty bad, as they were returned. I have tried using frozen angel food, pellets soaked in vitamins, even tried feeding sponge, we make sure that all thanks are properly grounded, Any suggestions??