Here, we present the first stickleback model of Hermansky-Pudlak syndrome, the spontaneous X-linked recessive casper phenotype, resulting from a frame-shifting insertion in Hps5. Hps5 mutants display oculocutaneous albinism, with severely decreased pigment in melanophores, iridophores, and erythrophores, though, interestingly, not xanthophores. The gene discussed is HPS5; the disease is Hermansky-Pudlak syndrome.