gramma has swollen eye

[lastlight]

As I mentioned in my 'find a nano fish' thread my gramme has been hiding since he was added. few moments ago was the first i've seen of him since adding him. he looks perfect as far as color and body goes except one eye is quite swollen. like a balloon.

what is this and can it correct itself? can it possibly affect my other fish? everyone else looks great. would be hard to get him where he is holed up. i also don't have another tank to perform treatments in.

thanks.