Phylum Chordata Bateson, 1885 - chordates
   Subphylum Vertebrata Cuvier, 1812 - vertebrates
     Pisces
       Class Actinopterygii Woodward, 1891 - ray-finned fishes
         Order Anguilliformes Rafinesque, 1810 - eels
           Family †Anguillavidae Hay, 1903
           Family Anguillidae Rafinesque, 1815 - freshwater eels
           Family †Anguilloididae
           Family Chlopsidae Rafinesque, 1815 - false morays
           Family Colocongridae Smith, 1976
           Family Congridae Kaup, 1856 - conger eels
           Family Derichthyidae - longneck eels
           Family Heterenchelyidae Regan, 1912
           Family †Milananguillidae
           Family Moringuidae Gill, 1885 - spaghetti eels
           Family Muraenesocidae Kaup, 1859 - pike conger eels
           Family Muraenidae Rafinesque, 1815 - morays
           Family Myrocongridae Gill, 1890
           Family Nemichthyidae Kaup, 1859 - snipe eels
           Family Nettastomatidae Kaup, 1859 - duckbill eels
           Family Ophichthidae Günther, 1870 - snake eels and worm eels
           Family †Paranguillidae
           Family †Patavichthidae see Family Patavichthyidae
           Family †Proteomyridae
           Family Serrivomeridae Trewavas, 1932 - sawtooth eels
           Family Synaphobranchidae Johnson, 1862 - cutthroat eels
           Family †Urenchelyidae Woodward, 1900