organ of locomotion and balance in fishes and some other aquatic animals

any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills

a tail fin with unequal lobes in which the vertebral column turns upward into the larger lobe as in sharks

symmetrical tail fin extending beyond the end of the vertebral column as in most bony fishes

any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills