It seems the eye is protruded.
What are the parameters in the tank?
And if you have the info for
and or others like
aka alkalinity / Calcium or general hardness
Fish will often pick on a sick one.
Try and use a breeder net to keep the bully fish in - if there is only one causing a problem, or the ill fish in if there are many picking on the sick one.
Fish will often get agitated and more aggressive when they are in unsafe water parameters.