Based on the unique fish fauna observed from a manned submersible on a southern Caribbean reef system in Curaçao, Smithsonian explorers defined a new ocean-life zone, the rariphotic, between 130 and 309 meters (about 400 to 1,000 feet) below the surface. The rariphotic occurs just below a previously defined reef zone, the mesophotic, which extends from about 40 to as deep as 150 meters (about 120-450 feet). The role of this new zone as a refuge for shallower reef fishes seeking relief from warming surface waters or deteriorating coral reefs is still unclear.