| 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 (knivefish) that are 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 valid species in two genera.[2] There are a number of undescribed species known in museum collections.
These fish are nocturnal and mostly occur in quiet waters from deep rivers to swamps. In strongly-flowing waters they may bury themselves.[1]
Like the other gymnotiforms, Gymnotids have a classic knifefish body. The body is long and eel-like, the dorsal fin and pectoral 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 metres (6.6 ft) length. Species of Gymnotus reach up to about 100 centimetres (3.3 ft) in length.[2]
There are 37 species in two genera:[3]