WARM-Blooded Fish Discovered For The First Time Ever

It's cold at 1,300 feet deep in ocean water. But nature helps moonfish keep warm.

The moonfish, or opah, is the world's first fully warm-blooded fish scientists have ever discovered.

About the size of a car tire, the moonfish, a predator, can move more quickly in frigid waters because of a personal heating system. The fish's special circulation, helped by a large heart and flapping fins, is more similar to mammals than to other fish.

And when you spend long stretches of time at 150 to 1,300 feet under water, warmth is definitely important.

"Nature has a way of surprising us with clever strategies where you least expect them," fisheries biologist Nicholas Wegner of NOAA Fisheries' Science Center in La Jolla, California said in a statement. "It's hard to stay warm when you're surrounded by cold water but the opah has figured it out."

Learn more about this bizarre fish here: