Chromatophoromas in two species of Hawaiian butterflyfish, Chaetodon multicinctus and C. miliaris.

Chromatophoromas (cutaneous pigment cell tumors) were seen in two species of butterflyfish, Chaetodon multicinctus and Chaetodon miliaris, over an 11-year period (1976-1987) in waters off the islands of Maui, Lanai, and Molokini in the state of Hawaii. The chromatophore tumors found in the brown-barred butterflyfish, C. multicinctus, were predominantly iridophoromas (characterized by the presence of birefringent olive-green crystalline pigment), while the tumors in the lemon butterflyfish, C. miliaris, were primarily melanophoromas (characterized by the presence of melanin pigment). Mixed chromatophoromas, composed of iridophores, melanophores, and undifferentiated chromatophores, were found in both species. The prevalence of chromatophoromas in C. multicinctus off the island of Maui varied from a low of 22-25% in 1976 to a high of 50% in 1987. The estimated prevalence of chromatophoromas in C. miliaris was 2.5% off the island of Molokini in 1976, and 5.0% off Lanai in 1987. The cause or causes of chromatophoromas in these two species of butterflyfish has not been determined.