A stingray that has left the bottom: dark purple, wedge-shaped, and living in the surface layer of the open ocean.
To about 80 cm across the disc, dark purple-grey above and below, with a distinctly wedge-shaped disc that is wider than it is long and a short thick tail. Nothing else on this site is a stingray in open water.
It is exactly that: a stingray that has left the bottom and lives in the surface layer of the open ocean, feeding on squid, jellyfish and small fish. At Cocos it is seen in the blue rather than on the reef. It carries a long venomous barb and the interactions on record are with fishermen rather than divers.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.