Congroidei is a

suborder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

of ray-finned fishes belonging to the order

Anguilliformes Eels are ray-finned fish belonging to the order (biology), order Anguilliformes (), which consists of eight suborders, 20 Family (biology), families, 164 genus, genera, and about 1000 species. Eels undergo considerable development from the earl ...

, the eels. These eels are mostly marine, although a few species of snake eel will enter freshwater, and they are found in tropical and temperate waters throughout the world.

Families and subfamiles

Congroidei contains the following extant

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

and subfamilies: * Family

Colocongridae The Colocongridae, the worm eels or short-tail eels, are a family of eels, containing a single genus, ''Coloconger''. Colongrids are found in tropical waters of the Atlantic, Indian, and West Pacific oceans. They are bottom-dwelling fish, living ...

D. G. Smith, 1976 (shorttail eels) * Family Derichthyidae

Gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

, 1884 (longneck eels or narrowneck eels) * Family

Ophichthidae Ophichthidae is a family (biology), family of fish in the order (biology), order Anguilliformes, commonly known as the snake eels. The term "Ophichthidae" comes from Greek language, Greek ''ophis'' ("serpent") and ''ichthys'' ("fish"). Snake eels ...

Günther, 1870 (snake eels and worm eels) ** Subfamily

Myrophinae Myrophinae, the worm eels, is a subfamily of ray-finned fishes belonging to the family Ophichthidae, which also includes the snake eels in the subfamily Ophichthinae. Taxonomy Myrophinae was first proposed as a subfamily by the German naturalist ...

Kaup, 1856 (worm eels) ** Subfamily

Ophichthinae Ophichthidae is a family (biology), family of fish in the order (biology), order Anguilliformes, commonly known as the snake eels. The term "Ophichthidae" comes from Greek language, Greek ''ophis'' ("serpent") and ''ichthys'' ("fish"). Snake eels ...

Günther, 1870 (snake eels) * Family Muraenesocidae Kaup, 1859 (pike conger eels) * Family Nettastomatidae Kaup, 1859 (duckbill eels) * Family Congridae Kaup, 1856 (conger eels) ** Subfamily Congrinae Kaup, 1856 (congers) ** Subfamily Bathymyrinae J. E. Böhlke, 1949 ** Subfamily Heterocongrinae Günther, 1870 (garden eels)

References

Eels Ray-finned fish suborders {{Anguilliformes-stub