Noun | 1. | ![]() animal order - the order of animals Malacopterygii, superorder Malacopterygii - an extensive group of teleost fishes having fins supported by flexible cartilaginous rays eel - voracious snakelike marine or freshwater fishes with smooth slimy usually scaleless skin and having a continuous vertical fin but no ventral fins Anguillidae, family Anguillidae - eels that live in fresh water as adults but return to the sea to spawn family Muraenidae, Muraenidae - marine eels Congridae, family Congridae - marine eels |