The affected skin may have pale patches and/or a characteristic sore or lesion shaped like a saddle across the dorsal fin.
Fluke larvae burrow into the flesh of the fish and form a cyst.
Melanosis is not an infection but an increase in the melanin in the skin.
Red, off-white, and white worms found under the skin, in the intestines, and in the body cavity.
The diseased flesh appears tough, granular, coarse, and yellow to brown, often resembling freezer-burned meat.
Tapeworm larvae (plerocercoids) often appear as white cysts or coiled worms in the flesh or internal organs.
The most common causes are three bacteria in the genus Aeromonas.
Fish have wartlike growths on the skin, fins, and occasionally gills.
Water molds (which are not true molds or fungi) appear as white, gray, or tan cottony growths on the skin of the fish when submerged in water.