Naso with tail rot??

[lngrhaul]

Recently moved my 180 gallon tank and put all the fish in a temp tank. After a short cycle, have been moving the fish and corals back into their home. all that is left is the 4 tangs.

I'm getting ready to move the tangs over and I've noticed a problem with the naso's tail. The orange part is now white - don't know if something is gone or if there is something white covering it. Hard to tell and he won't stay still.

Picture is not very clear but any ideas would help. Now I have to decide if I should move him over or not......and I really, really want to get the temp tank out of my new dining room