Tail fin knife eels

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Tail fin knife eels
White-fronted knifefish (Apteronotus albifrons)

White-fronted knifefish ( Apteronotus albifrons )

Overcohort : Clupeocephala
Cohort : Otomorpha
Sub-cohort : Ostariophysi
Order : New World Knifefish (Gymnotiformes)
Family : Tail fin knife eels
Scientific name
Jordan , 1923

The caudal fin knife eels (Apteronotidae) are a family of the New World knife fish (Gymnotiformes). The fish live in northern and central South America from the Río de la Plata to the Río Tuira in Panama . Distribution focus the greatest biodiversity is in the Amazon basin.


The body of the caudal fin knife eels is elongated like an eel and compressed laterally. As with all knife fish, the anal fin is elongated and has become the main driving organ. Ventral fins are missing, but a small caudal fin that is not connected to the anal fin is present in contrast to all other New World knife fish. There is a small, thread-like on the back dorsal fin that can be hidden in a skin groove. In some species the snout is extended like a trunk. The eyes are small, their diameter is smaller than the distance between the nostrils. Tail fin knife eels are 16 centimeters to 1.30 meters long. All caudal fin knife eels can use converted nerve cells to generate an electrical field that is used for orientation and communication with conspecifics.

Way of life

Little is known about the way of life of the caudal fin knife eels. They have a large share of the biomass in their home waters. They are not important for human nutrition. The white-forehead knifefish is exported on a larger scale for aquarium purposes.


Fishbase lists 89 species in 16 genera. It is to be expected that further species will be discovered and described anew in the future. The Apteronotidae are divided into two subfamilies.

Marbled knifefish ( Adontosternarchus balaenops )


Individual evidence

  1. Tail fin knife eels on Fishbase.org (English)
  2. ^ Maxwell J. Bernt, Victor A. Tagliacollo, James S. Albert: Molecular Phylogeny of the Ghost Knifefishes (Gymnotiformes: Apteronotidae). Molecular Phylogenetics and Evolution, March 2019, doi: 10.1016 / j.ympev.2019.02.019
  3. de Santana, CD and RP Vari, 2010. Electric fishes of the genus Sternarchorhynchus (Teleostei, Ostariophysi, Gymnotiformes); phylogenetic and revisionary studies. Zool. J. Linn. Soc. 159: 223-371.
  4. Bernt, MJ, Fronk, AH, Evans, KM & Albert, JS (in press): A redescription of deep-channel ghost knifefish, Sternarchogiton preto (Gymnotiformes: Apteronotidae), with assignment to a new genus. Neotropical Ichthyology, 18 (1): Epub Apr 17, 2020.