My clownfish has a white fluff on him on both sides of his head?

he's not necessarily actin diffferent. I am just concerned. we recently put a whitebelly pufer in that died within three days.. when we got him he had ich. we treated the ich and i am wondering if this is an impact of the ich medicine. IMy poor clown is one of three he is the largest and it looks like the only one impacted.