Fins: Help a fish move. The top fins are called dorsal fins. If there are two dorsal fins, the one nearest the head is called the first dorsal fin and the one behind it is the second dorsal fin.

The fish was “slender” and “fusiform,” and it had an adipose fin, a fleshy dorsal fin without bony ... and was found in iron-rich stone, researchers said. Thousands of new species are ...