Abstract
We present a patient with skin ulcers that did not respond to a 3-week course of treatment with amoxicillin-clavulanic acid. As the patient maintained a fish aquarium, mycobacterial infection was suspected. Indeed, reassessment of histopathology revealed acid-fast bacilli, and mycobacterial cultures at 30 °C grew Mycobacterium marinum. Eventually, surgical reconstruction of the tendons was needed.