This barrel eye fish is not going to win any beauty prizes. But it surely deserves admiration for its enormous telescoping eyes, housed in a transparent head that functions as a muscle-driven lens to scavenge what little light penetrates the inky ocean depths. The huge green lenses points to a retina with exceptional density of rod cells, packed with the light harvesting protein rhodopsin. Cone cells, that see color, are absent. Those two tiny openings on either side of its mouth? They are nostrils .
The fish spends most of its time motionless, eyes directed upwards to catch the shadow of prey emitting faint bioluminescence.
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