Some move freely over the body surface. As in other animals, tumors occasionally occur on fish. Physical Injury Predators, such as birds and other fish, can cause wounds and other malformities. Observed Externally Visual Signs Comments Lesions, sores, hemorrhages, fish pop-eyed, blood under scales, or loss of scales. Various species of bacteria can infect fish.
Symptoms vary depending on bacteria and fish species.
Bacterial infections are usually the result of a stress on the fish or infection of a wound. An infected fish is edible. Trim away infected flesh. Fungus may infect a wound or lesion. An infected fish is edible.