We report a case of Mycobacterium marinum infection in a lung transplant recipient who presented with nodules on the hand and forearm following exposure to fish-tank water of a superficial hand burn. Skin biopsy revealed granulomatous inflammation and fibrosis. Tissue culture grew Mycobacterium marinum. The patient underwent surgical excision of the lesions and treatment with ethambutol and azithromycin for 12 months and experienced complete resolution of the infection. Transplant recipients who receive immunosuppressive therapy are at increased risk for opportunistic infections. For a patient with nodular lesions on the extremities, exposure to fish, fish-tank water, or swimming should suggest infection with Mycobacterium marinum.