Could always try some more fresh foods. Fresh blender mush boosted with garlic and beta glucan to help boost the fish's immunity. Not an expect on sick fish but this is what I would do. I actually feed this every otherday to help keep my fish as healthy as possible.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,