The bicolor Damselfish, Stegastes partitus, has been the focus of biomedical research due to the high natural incidence of a transmissible cancer affecting the peripheral nervous system and pigment cells of this species and the unusual nature of the etiologic agent. These tumors are characterized as neurofibromas, malignant peripheral nerve sheath tumors and chromatophoromas. This disorder has been termed damselfish neurofibromatosis (DNF) because the plexiform neurofibromas in affected fish exhibit a similar histology to the hallmark lesions of Neurofibromatosis type 1 (NF-1) in humans. While a wide variety of naturally occurring and induced tumors in animals have been shown to be transmissible, DNF is the only naturally occurring tumor affecting either Schwann cells or pigment cells. To date, few animal models of NF-1 have been developed and while the gene responsible for this inherited diseased in humans has been identified, many aspects of the mechanisms which lead to tumor formation and malignant transformation are unknown. DNF may provide a unique perspective on this very common human disease. Despite the differences in etiology between NF-1 and DNF, a role for mitochondrial changes in NF-1 has been postulated but not fully investigated.