marks on salfin tang

[hybridazn]

hey guys i noticed some markings on my salfin tang today. when he is his darker shade they appear white but when he lightens up then turn a darker color. it doesnt appear like ich but i was hoping someone who has more experience with this can ID it for me. here are a couple pics, hopefully the quality is good enough to ID

thanks in advance!

*EDIT* his eating and other behavior have not changed nor is his breathing become rapid or slow.