I am sitting here imagining having 1 too many margaritas when a waiter comes and serve me the "catch of the day". Talk about not knowing whether to sh_t or go blind!
Maybe caught in their nets for awhile? Looks pretty beat up (rotted). While not washing up everyday, they are not uncommon. Very deepwater fish that come to the surface to die. There was a pair that beached themselves on San Marcos Island a few years back and some very good pictures taken of them while they were still alive. Huge fish.