Mycobacterium marinum is a type of bacteria that causes disease in fish, reptiles, and amphibians. It is spread to people and animals through contaminated aquarium water. All fish are susceptible to mycobacterium, but fresh water species seem to be most affected. This disease is slow growing in fish. Affected fish may stop eating, lose their fins or scales, develop sores, or appear deformed.
Though infection in humans is rare, people can become sick with mycobacteriosis after coming into contact with contaminated water through minor cuts and skin abrasions. People with this disease, commonly known as “fish tank granulomas,” develop warm raised, red areas of the skin. Skin lesions can leave long-lasting scars.
Reduce the risk for mycobacterium by washing your hands after handling reptiles, amphibians, and fish.
From the Center for Disease Control and Prevention (CDC)