sick tang

[nimosreef]

Hi,I have a yellow tang and on his fins has what looks like white cotton balls and his tail has a wound in it and on his head has a small pach where he does not have skin on, is white.He eats and is active.How do i treat him ?he is in a 150 with a lot of rock and corals and is very hard to get him out i also have 2 more tangs in the tank but there are fine.thanks