Hi again.
Recently one of my cardinal tetra got sick with what looks like pop-eye. I put him in a hospital tank and treated him with Mela-fix.
But he seems stressed all by himself and he's not eating. He was eating in the big tank with his mates but not now. I didnt want to leave him in there in case he passes on the disease.
He's not getting better -it's been four days and nothing has changed. I'm not sure how much longer he'll last not eating anything

.
Also, I'm not sure if it is pop-eye now, it looks more like a sac of fluid above the eye. And it's not actually pushing the eye out. Another thing, it looks like there is a small worm in the fluid sac, although this might be a bit of skin? I'm not sure.
Has anyone had a fish with symptoms like this? PLease help me!
Thanks