in the last week my yellow tang looks like its stomach area being sucked in . he eats normally swims all over the tank normally is this normal or is it sick
Try the nori. Get it dried or toasted from your local grocery store. No flavored stuff. If the algae clip freaks him out try to tie it around a small piece of LR.
If he's too bad you may want to soak some of it in vitamins before offering it.