I bought a blue tang a week and a half ago. 2 nights ago I noticed he has a whitish film on him, almost fuzzy. I'm assuming he has ich. Yesterday I did a 50% water change, added a protein skimmer, raised the temp to 84, and dropped salinity to 1.019 as recommended by my lfs. Yesterday before all of this, my little guy wouldn't even come out to eat. Today he is swimming around, eating galic soaked food, and the white film is about the same. My lfs said to put him into a qt tank would only stress him more. All other fish seem fine, a coral beauty, 2 clowns, saddled puffer, a green chromis, and bangaii cardinal. After reading several posts on this site I'm now wondering if I should transfer him and all fish to a QT tank? If this is the case, can I take some of my cc and water from my display tank and put in my to fill my 20 gallon tank?