I bough a Powder brown tang and a Pyramid butterfly fish that after a week they showed what seems to be ich: White small dots on their body, like salt.

Now they are in a hospital with hypo-salinity treatment. No sign of external ich, they eat well and appear healthy(no rubbing to surfaces or impaired swimming) . I tend to keep them for about 3~4 weeks.

TODAY, I noticed there is (at least appear to be) a hair out of my tangs month! He is still able eats well like before.

What could be the hair? What should I do?

P.S since for time being my Hospital/QT is a salt bucket, I can only look at them from above!

Thank you