The duckbill eels or witch eels are a family, Nettastomatidae, of eel

Eel

Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

s. The name is from Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 netta meaning "duck" and stoma meaning "mouth".

Duckbill eels are found along the continental slopes of tropical and temperate oceans worldwide. They are bottom-dwelling fish, feeding on invertebrates and smaller fish. They are slender eels, up to 125 centimetres (4.1 ft) in length, with narrow heads and large, toothy, mouths. Most species lack pectoral fins.

Species

There are about forty species in seven genera:

• Genus Facciolella
  Facciolella
  Facciolella is a genus of eels in the duckbill eel family Nettastomatidae. It currently contains the following species:* Facciolella castlei Parin & Karmovskaya, 1985* Facciolella equatorialis Facciolella is a genus of eels in the duckbill eel family Nettastomatidae. It currently contains the...
  
  
• Genus Hoplunnis
  Hoplunnis
  Hoplunnis is a genus of eels in the duckbill eel family Nettastomatidae. It currently contains the following species:* Hoplunnis diomediana Goode & Bean, 1896...
  
  
• Genus "Leptocephalus"
  Leptocephalus (genus)
  Leptocephalus is a genus that was used for species of larval eels, called leptocephali, that were thought to be new fish species, or whose adult eel species were not known...
  
  
• Genus Nettastoma
  Nettastoma
  Nettastoma is a genus of eels in the duckbill eel family Nettastomatidae. It currently contains the following species:* Nettastoma falcinaris Parin & Karmovskaya, 1985* Nettastoma melanurum Rafinesque, 1810...
  
  
• Genus Nettenchelys
  Nettenchelys
  Nettenchelys is a genus of eels in the duckbill eel family Nettastomatidae. It currently contains the following species:* Nettenchelys dionisi Brito, 1989* Nettenchelys erroriensis Karmovskaya, 1994...
  
  
• Genus Saurenchelys
  Saurenchelys
  Saurenchelys is a genus of eels in the duckbill eel family Nettastomatidae. It currently contains the following species:* Saurenchelys cancrivora W. K. H. Peters, 1864...
  
  
• Genus Venefica
  Venefica
  Venefica is a genus of eels in the duckbill eel family Nettastomatidae. It currently contains the following species:* Venefica multiporosa Karrer, 1982* Venefica ocella Garman, 1899...