Freshwater Tropical · Marine / Saltwater
Mycobacteriosis (Fish Tuberculosis)
A slow, chronic infection caused by Mycobacterium spp. Symptoms include emaciation, spinal deformity, and granulomas. Zoonotic risk — handle with care.
Severity: Critical
Mycobacteriosis is one of the most under-diagnosed diseases in the aquarium hobby. The progression is slow — weeks to months — and symptoms mimic many other conditions. The pathogen forms granulomas in internal organs and is **zoonotic**: it can infect humans through skin breaks.
Causes
*Mycobacterium marinum* is the most common species. Transmission occurs through contaminated food, water, or cannibalism of infected dead fish. Anabantoids (gouramis, bettas) and seahorses are particularly susceptible.
Treatment
There is no reliable cure. Severely affected fish should be humanely euthanised. In valuable specimens, a prolonged course of kanamycin combined with rifampin has shown partial success but treatment is months long. **Always wear gloves when handling infected fish or contaminated water.**
Recommended medications
Antibiotic
Nitrofuracin Green
Wide-spectrum antibacterial and antifungal. Excellent for new fish, ammonia burn, transport stress, and quarantine.
from $32.00
Recommended equipment
Hardware that prevents, monitors, or treats this condition — listed with the most important first.
Filtration
Activated Carbon Filter
Medication removal after treatment, toxin adsorption
from $5–$50
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Feeding Systems
Medicated Food Maker
Delivery of oral antibiotics and medications
from $600–$1200
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Monitoring
Microscope for Fish Health
Definitive parasite and pathogen identification
from $100–$800
View details →Prevention
Strict quarantine. Avoid live foods of unknown origin. Disinfect equipment between tanks. Never gravel-vacuum a tank with known mycobacteriosis into a healthy tank.
Frequently asked questions
Can I catch fish TB from my aquarium?
Yes. *Mycobacterium marinum* causes "fish-tank granuloma" in humans — skin lesions, usually on the hands. Always wear gloves when working in a tank where mycobacteriosis is suspected.
Should I treat the whole tank?
Generally no. There is no reliable cure, and mass-medicating with kanamycin for months is rarely justified. Cull affected fish, deep-clean, and start over with quarantined stock.