The tiny adipose fin, a fatty nub between the dorsal fin and tail of some 6,000 species of fish, has been the ugly stepchild of anatomy. Most scientists shrugged and dismissed it as a withered ...

These fish have evolved highly specialized jaws for fin-eating. When they’re young, some of them eat smaller fish whole, but by the time they become adults, they really only care about chomping ...

The small, ear-shaped adipose fin is located on top of the fish, to the left of the larger dorsal fin. On a clipped-fin fish, this fin would be missing. (credit: Michigan Department of Natural ...