Yellow tang white blotch on lateral line

My yellow tang has an irregular white blotch running along it's lateral line on one side. It also has a couple of fin tears, but those have come and gone in the past.

Everything else with the tank is fine, and I have had the yellow a year and a half with no problem.

Thanks for any advice!

Nothing brown, red or other...just white. The irregular blotch runs along the curved line in upper part of body, sort of parellel to the dorsal fin...I assume that curved line is the lateral line. Also on that same side, lower body appears more whitish...other side is more totally yellow, as it has always been.

No other symptoms...seems to swim and eat fine, and all other fish, together now at least a year, are also fine.

Maybe some of the yellow has just faded, as you say.

BTW, you have always been very helpful, responsive and courteous...I appreciate it!