A new paper published by the Grossman, Pringle and Palumbi labs from Stanford University was published in Current Biology (PMID:24012312). Typically, coral bleaching is induced by the generation of reactive oxygen species (ROS) under high light conditions. Interestingly, Tolleter and colleagues find corals as well as Aiptasia respond to periods of heat with bleaching even in the absence of light. The so-called dark bleaching could be an additional mechanism compromising the fidelity of coral reefs during the summer. The paper also nicely demonstrates how lab experiments using Aiptasia as a model system for corals complement coral field studies.