that is really strange .... last week I had the exact same issue . . My male Cuban got into a fight with my polleni bit him in the eye and 4 days later it was cloudy and swollen and he was hiding . I took a 20 L Rubbermaid tub and put 10 gallons of tank water in it . I then put 4 teaspoons of Epsom salt in the tub and went to the fish store picked up some erythromycin . I added a airstone on the first day I added a package of the em erythromycin in threw the fish in. after 24 hours I put another package in. Third day I did a 25 % water change and added another package. 24 hours later I did another 25 % water change (2.5 gallons ) and added another package. 4 days of treatment is all you need for this med. It is very strong . I put him back into the main tank and his eye is not swollen anymore but the top part where the intial bite is still there. he is not hiding anymore . I have been doing a 25 % water change on the large tank every two days and it is improving. I almost forgot to mention to add a small heater to the tub. I treated in Rubbermaid tub sice the erythromycin will do damage to your beneficial bacteria .