Sick Blue Gourami!! Pop-eye?

[saulog]

yesterday i noticed that my blue gourami had developed some kind of bump on top of his or in his eye i cant distinquish it well. it looks like the inside of his eye just popped out or something. i really want to help him and dont want him to die. doest anybody know what this is or how to cure him? i checked my water parameters and they seem fine. ammonia 0, nitrite 0-0.25( cant tell one or the other), nitrate 5 ppm. i posted a picture for reference.

 

[reefdiver]

plenty of clean water will help.