Chocolate tang with a cloudy eye

When chocolate gets a little gray in spots it means it's getting old and needs to be eaten.  Put 'im on the BBQ. It may sound crazy but I had BBQ Yellow Eye Tangs at a wedding reception in Hawaii a few years ago. Mmmm tastes like fish.

Seriously though, it shouldn't be a problem and should go away on it's own, but just to check, what is it's environment like? As usual, I have several questions:

Can you show us a pic of the tank, please?

Also, you say it's grazing all day, on algae, I assume?

What kind of algae is presently growing in the tank?

Is there a Refugium with Macroalgae?

What supplemental food is it being fed and does it periodically get this additive in the food? I'd add that every other day for the next week to help the fish fight off any issues, like infection, etc.

This could become Pop-Eye for which there is no absolute remedy except what seems to help is a healthy, stress free environment with plenty of good natural food.

Aloha,

Mark