The yellow black-faced triplefin deflects sunlight to break predator camouflage
(PHYSorg.com Biology)

Small fish use light for active sensing to detect potential predators. The yellow black-faced triplefin (Tripterygion delaisi) can reflect downwelling sunlight sideways with its iris, illuminating its immediate surroundings. A team headed by Professor Nico Michiels from the Institute of Evolution and Ecology at the University of Tübingen has now shown that the fish actively reflects light to locate predators such as the Black Scorpionfish (Scorpaena porcus). When the deflected sunlight hits the eyes of a scorpionfish, it is reflected back - and warns the triplefin to keep a safe distance. The results of Michiels` team have been published in the latest Proceedings of the Royal Society B.