A family of small freshwater fish found in South America, notable for their transparent bodies and distinct visual systems.
From Greek 'diopter' (the lens/seeing) with Latin scientific suffix '-idae' (family), named for their characteristic transparent bodies that allow light to pass through.
Dioptidae fish are called 'transparent fish' and some species have completely see-through heads with tubular eyes that rotate upward—they're literally what you'd get if you tried to build the 'see-through' concept into a living creature.
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