Popeye is more a condition than it is a disease. In saltwater fish it may affect one or both eyes, appearing as if the eye has air or fluid trapped inside, around or behind it, causing the eye to enlarge and bulge out of its socket, as if under pressure. Duration of this condition can be anywhere from several days to several weeks.
A variety of physical injuries or non-infectious and infectious diseases can lead to this clinical condition.
Probable Causes - Trauma to the eye is usually the reason a fish has this condition when only one eye is affected. Eye trauma can be attributed to a scratch, scrape of bruise to the eye from encounters such as fighting with other fish, net abrasion, or coming into contact with a stationary object or organism in the aquarium, and may be bacterial or fungal in nature as well. In most cases where popeye occurs from eye trauma, the unsightly looking eye does not seem to affect the fish's overall good health.
Treatment - In cases where eye trauma is involved it is suggested to not remove the fish from the aquarium, unless harassment from other fishes is becoming a threat. Handling of the fish can cause further irritation to the eye, as well as additional trauma. In most minor cases the injury will heal in time as the condition is allowed to run its course. To help aid in the continued health and healing of the fish during the course of this condition, oral feedings of foods soaked in selcon or another type of liquid vitamin. Eventually the eye will deflate, but may result in various conclusions.
-In minor eye trauma situations, the eye will usually return to its normal appearance without blindness.
-In more serious cases where treatment is not provided or proves to be ineffective, the eye may appear colorless and gray, resulting in blindness to the eye, but is not necessarily fatal.
-In cases where one or both eyes have sustained severe trauma and treatment is not provided or proves to be ineffective, the eye(s) may burst or disappear altogether. This can be such a traumatic event that the fish may not recover and death will occur.