water in the eye?

[mr.wilson]

As fishtime has stated, your fish has pop-eye (exophthalmus). This is a symptom of either physical damage and or a bacterial infection. If it is bacterial, kanamycin or chloramphenicol are the best treatments. Be very careful if catching the fish to assure it doesn't get further damage. Eye tissue grows back very well. In some cases, the eye develops gas bubbles in the eye. If this happens, you need to pop it with a sterile needle, then clean the wound with an oxidizing agent such as iodine, potassium permanganate, or peroxide.

If the fish has no other signs of bacterial infection, such as cloudy fins, red lesions, or torn fins, then it is probably just a war wound. If the fish shows any other symptoms isolate and treat with a broad spectrum antibiotic and isoniazid for tuberculosis (Mycobacteria marinum).