It’s one of the most basic biology facts we’re taught in school growing up: Birds and mammals are warm-blooded, while reptiles, amphibians and fish are cold-blooded. But new research is turning this well-known knowledge on its head with the discovery of the world’s first warm-blooded fish — the opah.
The Giant Oarfish is the longest bony fish, reaching a confirmed length of up to 11m with unofficial accounts of up to 17m in length. Rarely seen alive, they occasionally wash up on shores, or are caught as bycatch in fishing nets. As a deep-sea fish, the Oarfish sports reduced mineralization in their bones due to the low mineral content of their environment, resulting in bendy, semi-translucent bones. Unlike most fish, the Oarfish lacks scales. Their flesh is gooey and gelatinous, and unpleasant to eat.
