Purple tang fin

[urodude]

My purple tang as minor erosion at the back of the doral fin. I doubt he is being picked at as he is the dominant fish in my reef tank.
There are no parasites, rash, slime, etc to indicate infection. He otherwise is eating and acting fine. Water parameters are perfect across the board.
Anything to worry about?

 

[beth]

May be head and lateral line erosion starting. Can you post a picture?