1. Distribution patterns of 3919 species of Indo-Pacific reef fishes were analysed using GIS mapping software for the purpose of conservation prioritization of extraordinary high concentrations ('hotspots') of diversity and endemism. 2. Megadiversity Countries with more than 1000 coral reef species include Indonesia, Australia, Philippines, Papua New Guinea, Malaysia, Japan, Taiwan, Solomon Islands, Palau, Vanuatu, Fiji, New Caledonia, and the Federated States of Micronesia. 3. The richest area for reef fishes is the renowned Coral Triangle, which includes eastern Indonesia, Sabah (Malaysia), Philippines, Papua New Guinea, and the Solomon Islands. The highest concentration of species within this region extends from south-eastern Indonesia to the central Philippines. 4. Occupying only 3% of the surface area of the tropical Indo-west and central Pacific, the heart of the Coral Triangle contains 52% of its total species. 5. The top-ranked areas based on percentage of endemism are Easter Island, Baja California, Hawaiian Islands, Galapagos Islands, Red Sea, Clipperton Island, Marquesas, Isla del Coco, Mascarene Islands, and Oman. 6. The highest concentration of endemics per unit area occurs at remote south-eastern Polynesian and eastern Pacific islands including Clipperton, Isla del Coco, Easter, Rapa, and the Pitcairn Group. Copyright (c) 2007 John Wiley & Sons, Ltd.