National Geographic : 1952 Feb
200 National Geographic Photographer Luis Marden These Fish Lie Down to Sleep. Each Brilliant Coral Dweller Selects Its Bed During day the pen at the Lerner dock flashes with life as the electric-blue markings of queen triggerfish (inset) and other denizens catch the light. At sunset the caged fish patrol their chosen spots, chasing away finny intruders. As darkness falls, all movement ceases and the fish lie flat in sand or among rocks and coral, as in these flash photographs. Bigger fish select the best beds, banishing weaker rivals to outlying "slums" to sleep crowded six deep against the pens' wire fence. Some species bury themselves in sand with only mouths projecting; others pass the night in abandoned shells. Having no eyelids, fish sleep with eyes wide open.