Mycobacterium marinum is a non-tuberculous photochromogenic mycobacterium, commonly responsible for fish and amphibious infections world-wide. Contagion in humans typically follows minor hand trauma from aquarium keeping and manifests as a granulomatous infection of the skin. Dissemination is rare and almost exclusive to immunosuppressed hosts. 15 cases of M. marinum fish tank related infection are hereby reported. The site of infection was the upper limbs in all cases. 3 patients presented a single papulo-verrucous lesion, while the remaining 12 showed a sporotrichoid clinical pattern. Diagnosis was reached by history and clinical examination and further supported by one or more of the following criteria: histology, culture, acid fast bacilli identification from histologic specimen and PCR. 2 to 3 months minocycline treatment showed efficacy in 13 individuals, another case was treated with rifampicin-isoniazid association, yet another showed spontaneous regression over a 3 month period.