Blue tang is not doing well

[rattslik]

This morning I woke up to my blue tang stuck to where the water leaves the tank. I thought nothing was wrong. I come back a few hours later to not see my tang. He was still on that spot. I push the tang and he swims off. But it has one swollen eye what would cause tgis

 

[ndrwater]

Doesn't sound good. Swollen eye is oftentimes a bacterial infection. But allowing itself to be stuck to the overflow rarely ends well for the fish.
How old is the system and what are the basic water parameters? Knowing the basics like Ammonia, Nitrite and Nitrate is a start. As is pH, temp and salinity.
We can help further the more info available to have an educated answer to the problem

 

[Chrisfish]

Bump