Is my Fish Sick

[goldhopper]

I just added a Harlequin Tusk to my tank. He swam around for five minutes and found a place to hide. I then noticed my Kole Tang had a spot on both sides of him. I am not sure if this is from stress or something else is going on. I was out of town for two days so my wife was feeding the fish did not notice anything. All of my other tangs and fish are ok. I hope it is stress and it will go away.