Veterinar, Vol. 64 No. 1, 2026.
Professional paper
https://doi.org/ISSN 0303-5409
Mycobacteriosis in a Marine Aquarium – Fish Tuberculosis with Zoonotic Potential
Helena Glumpak
; Specijalistička veterinarska praksa Bojanić, Zagreb
Krešimir Matanović
; Department of Biology and Pathology of Fish and Bees, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia
*
* Corresponding author.
Abstract
Mycobacteriosis is an infectious disease affecting numerous species of freshwater and marine fish, caused by acid-
fast bacteria of the genus Mycobacterium, primarily M. marinum, M. fortuitum, and M. chelonae. These pathogens are
widely distributed in the aquatic environment and sediment, exhibiting high resistance to physico-chemical factors
and an innate resistance to numerous antibiotics. The pathogenesis of mycobacteriosis is based on survival of mycobacteria
within macrophages, resulting in the formation of characteristic granulomatous inflammatory processes, most
commonly in parenchymal organs such as the spleen, liver, and kidneys. The disease typically manifests in a chronic
form with non-specific symptoms, while carriers play a crucial role in the spread of infection within the ornamental
fish trade. Diagnosis relies on the clinical presentation, histopathological findings of granulomas, and the detection
of acid-fast bacteria using Ziehl-Neelsen staining. Given that treatment in fish is generally unsuccessful and the use
of antitubercular drugs is ethically questionable due to the risk of developing resistance in humans, radical measures
such as euthanasia of infected individuals and thorough disinfection of the aquarium are recommended. The disease
is of particular significance due to its zoonotic potential, as direct contact with contaminated objects and water can
cause a disease in humans characterized by specific skin lesions, also known as “fish tank granulomas”.
Keywords
Mycobacteriosis; Mycobacterium spp.; granulomatous inflammation; ornamental fish; zoonosis
Hrčak ID:
348971
URI
Publication date:
8.7.2026.
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