This is the first fully warm-blooded fish
At first glance, the opah looks like a giant, bloated disc armed with oh-so-puny fins. The two-meter-long creature is fun to look at, and maybe laugh at, but it’s got a lot more to share with you than its looks. As it turns out, it’s the only “truly warm-blooded fish,” according to National Geographic — and it’s pretty fast, to boot.
Source:: The Verge