Is the eye hazy at all? To me it looks like he rubbed his eye against a rock or something and just has a little injury. If I'm right clean water and extra water changes will get him back in shape in no time.
Feed your Filtration
Give it to Porc Chop he'll eat anything!!!!!
"This is my tank and these other fish just live in it"
^ Quoted from Porc Chop^