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

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.

Freshwater Tropical

Mycobacteriosis (Fish Tuberculosis)

A slow, chronic infection caused by Mycobacterium spp. Symptoms include emaciation, spinal deformity, and granulomas. Zoonotic risk —…

Critical

Freshwater Tropical

Mycobacteriosis (Fish Tuberculosis)

A slow, chronic infection caused by Mycobacterium spp. Symptoms include emaciation, spinal deformity, and granulomas. Zoonotic risk —…

Critical

Freshwater Tropical

Mycobacteriosis (Fish Tuberculosis)

A slow, chronic infection caused by Mycobacterium spp. Symptoms include emaciation, spinal deformity, and granulomas. Zoonotic risk —…

Critical

Freshwater Tropical

Mycobacteriosis (Fish Tuberculosis)

A slow, chronic infection caused by Mycobacterium spp. Symptoms include emaciation, spinal deformity, and granulomas. Zoonotic risk —…

Critical