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Bacterial 🔴 Fatal

Mycobacteriosis (Fish Tuberculosis)

🦠 Mycobacterium marinum, M. fortuitum, M. chelonae · Mycobacteriaceae

📋 Definition

A chronic granulomatous disease of fish caused by acid-fast mycobacteria, forming granulomas throughout visceral organs; a significant zoonosis causing "fish tank granuloma" in humans.

📊 Key Facts

Causative Agent
Mycobacterium marinum, M. fortuitum, M. chelonae
Agent Family
Mycobacteriaceae
Peak Mortality
10%
Onset to Peak
months
Geographic Range
Worldwide — freshwater and marine systems
Transmission Routes
Ingestion of infected tissue, water-borne
Primary Host
Wide host range: striped bass, cichlids, ornamental fish; also human zoonosis
Treatment
✗ None
Vaccine
✗ None / Experimental
First Described
1897

🩺 Clinical Signs

Chronic wasting, ulcerative skin lesions, skeletal deformities (spinal curvature), scale loss, granulomas in internal organs.

🔬 Symptoms

🔬
Chronic wasting
Systemic Chronic
🔬
Spinal deformity
Musculoskeletal Chronic
🔬
Ulcerative skin lesions
Integumentary Chronic
🔬
Visceral granulomas
Systemic Chronic

🧪 Diagnosis

Acid-fast staining, PCR, culture (slow — weeks to months on Middlebrook 7H10).

💊 Treatment

⚠️ No universally approved treatment is currently available. The information below covers supportive care and experimental approaches.
No effective treatment — infected fish should be culled. Tank must be thoroughly disinfected.

🛡️ Prevention

ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Quarantine all new fish, good biosecurity, avoid skin contact with tank water if immunocompromised.