Symptoms of zoonotic fish diseases may include:
- Skin ulcers, blistering, dimples, or nodules
- Inflamed or enlarged lymph nodes
- Shortness of breath, difficulty breathing,
- Coughing up mucus
- Headache
- Skin swelling, tenderness, pain, warmth, or itching
- Fever or chills
- Joint pain, swelling, or stiffness
- Muscle aches or pain
- Fatigue or drowsiness
- Weight loss or loss of appetite
- Swelling of the feet, legs, or abdomen
- Stiff neck,
- Sensitivity to bright light
- Nausea and vomiting
- Diarrhea
- Confusion, delirium, or altered mental status
- Seizures
- Lightheadedness
- Rapid heartbeat
Risk
Transmission of zoonotic disease from fish are typically through direct contact between an individual, often with a fresh, open wound or other skin damage and an infected fish (live or dead) or contaminated water. Any person with open skin sores, wounds or scrapes should avoid direct fish contact and should not immerse or splash wounded skin with aquarium water. Transmission of pathogens has also occurred due to ingestion of contaminated water. There are increased risks to immunodeficient or immunosuppressed individuals.
Mycobacterium
Various Mycobacterium species including Mycobacterium marinum, M. fortuitum and M. chelonae and others can be found in a diverse variety of fish species. All can be associated with acute or chronic disease in fish, but most fish are long-term carriers before clinical disease is detected. Some of these species, such as M. marinum and M. haemophilum, are more virulent and can be transmitted to people via direct contact with fish (live or dead) or contaminated water in ponds or aquaria, where bacterial penetration can be facilitated by skin wounds or damage. Other Mycobacterium spp. mainly infect immune-compromised individuals.
Persons affected by mycobacteriosis may develop “fish tank granulomas”, which appear as skin ulcers or nodules usually on the hands. Immunosuppressed persons can develop lymphadenitis & pulmonary disease similar to tuberculosis or more severe disseminated disease.
Streptococcus
Streptococcus iniae is a gram-positive bacterium carried by freshwater and marine species. Most persons have been infected via an existing wound or fresh puncture wound while handling live or dead fish.
Symptoms may include cellulitis, arthritis, endocarditis, meningitis, or death in infected persons.
Erysipelothrix
Erysipelothrix rhusiopathiae is a common water pathogen that may also be acquired by fish contact on an existing or fresh skin wound.
Persons with erysipelas may develop a local skin infection, a widespread skin infection or a systemic infection which can spread to the heart and heart valves.
Campylobacter, Aeromonas, Vibrio, Edwardsiella, Escherichia, Salmonella and Klebsiella
Campylobacter, Aeromonas, Vibrio, Edwardsiella, Escherichia, Salmonella and Klebsiella are other pathogens which may be transmitted by contact with abraded skin or wounds or accidental ingestion of contaminated water, food, or other materials. Aeromonas is more often associated with freshwater species, and Vibrio is more likely in saltwater species.
Contact may result in wound infections and ingestion can result in gastroenteritis with vomiting and diarrhea. More severe & potentially life-threatening disease and septicemia may occur in immunosuppressed people.
Revision History
07-2025 v.1