Naked-back knifefish
| Naked-back knifefishes | |
|---|---|
 | |
| Electric eel, Electrophorus electricus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Gymnotiformes |
| Suborder: | Gymnotoidei |
| Family: | Gymnotidae |
The naked-back knifefishes are a family (Gymnotidae) of knifefishes found only in fresh waters of Central America and South America.[1] All have organs adapted to the exploitation of bioelectricity. The family has 33[2] or 40[1] valid species in two genera. These fish are nocturnal and mostly occur in quiet waters from deep rivers to swamps. In strongly flowing waters, they may bury themselves.[1]
Physical characteristics
Like the other gymnotiforms, gymnotids have classic knifefish bodies. The body is long and eel-like, the dorsal fin and pelvic fins are absent, and the anal fin is extremely long and used for movement.[1]
The sole member of Electrophorus is the electric eel, which produces both strong (up to 600 volts) and weak (<1 V) electric discharges, for use in predation and communication/navigation, respectively. The electric eel is the largest of the gymnotiform fishes, growing up to more than 2 m (6.6 ft) length. Species of Gymnotus reach up to about 100 cm (3.3 ft) in length.[2]
These knifefish also use electricity to assist in their movement and navigation in the water due to their limited visibility, or in some cases, blindness.[3]
Genera
The 40 species are in two genera:[4]
- Electrophorus (monotypic)
- Gymnotus (39 species)
References
- 1 2 3 4 Froese, Rainer, and Daniel Pauly, eds. (2007). "Gymnotidae" in FishBase. April 2007 version.
- 1 2 Nelson, Joseph, S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
- ↑ http://www.practicalfishkeeping.co.uk/content.php?sid=4889
- ↑ Froese, Rainer, and Daniel Pauly, eds. (2011). "Gymnotidae" in FishBase. December 2011 version.