Off the coast of Queensland, in north-eastern Australia, lies the Coral Sea, a beautiful blue bit of ocean that covers the world’s largest coral reef system, the Great Barrier Reef. From space, the Great Barrier Reef looks like a string of gem-toned jewels lying roughly parallel to the Australian coastline. In fact, the Reef is made up of over 2,900 individual reefs and about 900 islands. Created by coral polyps, the Reef not only originated from living organisms, it also serves as home for a huge diversity of life. According to the United Nations Educational, Scientific and Cultural Organization (UNESCO), which adopted the Great Barrier Reef as a World Heritage Site in 1981, it contains not only the world’s largest collection of coral reefs, with 400 types of coral, but the Reef also supports 1,500 species of fish and 4,000 types of mollusk. It also is an important habitat of species such as the dugong (‘sea cow’) and the large green turtle, which are threatened with extinction. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured this beautiful true-color image on August 10, 2012. The tip of Queensland, which holds Lakefield National Park in the southeast section of the image and Mungkan Kandu National Park in the northwest, bears the typical tan color of a late winter landscape. A few clouds stream over the Coral Sea and over the northeastern-most tip of the land, while the Great Barrier Reef shines in the blue waters just off the coast. On August 1, 2012, PLOS One, an international, peer-reviewed, open-access, online scientific publication, published a study that, for the first time ever, identified melanoma found in the skin of a wild fish population. Scientists from Newcastle University in the United Kingdom diagnosed this skin cancer in 15% of the coral trout (P. leopardus) collected from several of the reefs in the Great Barrier Reef. In domestic fish species, in cats and in humans, an increase in incidence of melanoma is correlated to increased exposure to UV radiation. Melanoma is often an aggressive and fatal type of cancer. The appearance of this syndrome in an economically important species of fish within the Great Barrier Reef raises significant questions, including potential links to increases in UV radiation from stratospheric ozone depletion - alone or in combination with other environmental stressors, the effect of melanoma on the health and longevity of affected coral trout, and the impact of the newly-recognized disease on other fish species and other reefs.