Zebrafish larvae are an excellent model for investigating melanocyte development and disease. A: Lateral brightfield image of a 3-dpf larvae (original magnification, 3×). Two types of pigment cells, black melanophores and yellow xanthophores, are visible throughout the larvae (indicated by black arrows). The retinal pigment epithelium or eye, indicated by “e,” also contains black pigment or melanin producing cells. B: Dorsal image of 5 dpf zebrafish head (original magnification, 20×). Zebrafish melanocytes offer opportunities to study organelle trafficking by means of analysis of melanosome aggregation/dispersal (red arrowhead and black arrow, respectively) and mechanisms of drug resistance due to ease of adding drug of interest to surrounding fish water. C: Like human skin, zebrafish skin is organized into layers, the epidermis and dermis, with the basement membrane in between. Dermal endothelial cells (green), fibroblasts (purple), and pigment cells (black, yellow, and silver) are found in the dermis. Drawing created using Le Guellec et al., 2004.