Can anyone please i.d and advise?

[STORM]

Can anyone please share any input of what appears to look like scrapes on both sides of my blonde naso tang, i have had the fish for about 6 months and about a week ago these marks appeared on both sides of his body, i did a little research on line and its supposed to be caused by stress and with time its suppose to fade away, if anyone has had this issue i would appreciate any advise i can get, also checked all my water parameters and there all in check and as far as fish he is the only one with these marks and i dont see any other fish picking on him. Thanks in advance

 

[Exotic Reef]

What size tank is it in ? And did you add any new fish recently ?

 

[STORM]

no new fish and or coral and he`s in a 150 gallon tank.