Deepwater dweller is first known warm-hearted fish
Unlikely opah can keep much of its body warmer than its cold sea surroundings
![opah](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/05/sm_warm-blooded-fish_feat_free.jpg?fit=860%2C460&ssl=1)
BIG FISH A fish called an opah, studied here by researchers, is now proposed to be as about as close to a full-body warm-blooded fish as science has yet discovered.
NOAA Fisheries West Coast/Flickr (CC BY-NC-ND 2.0)