Hello everyone, I am searching from so advice regarding this recent blemish that has appeared on my pollenei Grouper. The fish has been in my tank for roughly a year and is one of the older members of my tank. to give some information regarding my tank. The tank is a reef ready 180gal 72 x 24 x 24 however i have a water volume of roughly 220 gallons between my two sumps. Filtration consists of an AC 110, Fx5, Eshopps 300 wet dry, and a custom system contain marine bio pure and bio rings. I also have an 18watt deep blue UV sterilizers that sits in on of the sumps. I have never had any ammonia, nitrite, or nitrate since my cycle. Tank mates dont seem to be an issue as the grouper is disregarded by the rest of the fish in the tank. Feeding consists of a slurry of foods krill, mysis shrimp, table shrimp, silversides, and chopped mussel and squid depending on what is on sale. To me it appears likely to have damaged his eye on some live rock. No other of his tank mates exhibit similar damage. 
I figured I should consult some experts.
I figured I should consult some experts.