Banded knife eel
| Banded knife eel | ||||||||||||
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Banded knife eel, drawing from The Naturalist on the River Amazons by Henry Walter Bates . |
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| Scientific name | ||||||||||||
| Gymnotus carapo | ||||||||||||
| Linnaeus , 1758 |
The banded knife eel ( Gymnotus carapo ) is a freshwater fish from the order of the New World knife fish (Gymnotiformes). It occurs in Central and South America from southern Mexico to Paraguay and also inhabits the Caribbean island of Trinidad . The species was classified in his Systema Naturae as early as 1758 by Carl von Linné , the founder of modern botanical and zoological taxonomy .
features
Banded knife eels reach an average length of 60 cm, with a maximum length of 76 cm. The body, covered by numerous, very small scales, is elongated, eel-like, almost round in cross-section at the front, increasingly flattening laterally towards the rear, and tapering at the end. The mouth is wide, the teeth arranged in a row conical. A caudal fin is missing, as are the dorsal fin and pelvic fins. The long anal fin , which extends almost the entire length of the body, is the main driving organ of the fish. It enables them to swim both forwards and backwards through undulating movements and is supported by 200 to 260 fin rays. The pectoral fins are supported by a hard fin ray and 14 to 15 soft rays. Young banded knife eels resemble the juvenile fish of the related electric eels and are flesh-colored to gray-yellow, usually patterned with numerous, broad dark brown to brown-gray horizontal stripes that are connected to one another on the back. But monochrome juvenile fish without horizontal stripes also occur. Adults are dark and show light-colored bars.
The fish have a weak electrical organ that is used for orientation and to differentiate between prey, competing conspecifics and predators.
Subspecies
Due to the wide range of the species, it covers 14 million km², it is very variable and polytypic. Therefore, seven subspecies were described in September 2017.
- Gymnotus carapo australis Craig et al., 2017, catchment area of Paraná and Río Paraguay ,
- Gymnotus carapo caatingaensis Craig et al., 2017, catchment area of the Rio Parnaíba in northeastern Brazil,
- Gymnotus carapo carapo Linnaeus, 1758, Suriname and French Guiana ,
- Gymnotus carapo madeirensis Craig et al., 2017, catchment area of the upper Rio Madeira ,
- Gymnotus carapo occidentalis Craig et al., 2017, catchment area of the western Amazon, the Rio Negro and the Essequibo ,
- Gymnotus carapo orientalis Craig et al., 2017, Catchment area of the eastern Amazon, the Rio Tocantins and the Rio Trombetas ,
- Gymnotus carapo septentrionalis Craig et al., 2017, catchment area of the Orinocos and Trinidad .
Way of life
Banded knife eels live in fast and slow flowing, in stagnant small bodies of water and in the shady bank areas of larger rivers. Since they are able to take in air, they can survive the drying out of their living waters for a while. The nocturnal fish feed on worms, insects ( dragonfly larvae ), small fish, especially tetras and plant material. The species lays its eggs in a nest made of plant material, later the male takes eggs and larvae into its mouth ( mouthbrooders ).
literature
- Günther Sterba : The world's freshwater fish. 2nd Edition. Urania-Verlag, Leipzig et al. 1990, ISBN 3-332-00109-4 .
- Günther Sterba (Ed.), Gert Brückner: Encyclopedia of Aquaristics and Special Ichthyology. Neumann-Neudamm, Melsungen u. a. 1978, ISBN 3-7888-0252-9 .
Individual evidence
- ↑ Craig, JM, Crampton, WGR & Albert, JS (2017): Revision of the polytypic electric fish Gymnotus carapo (Gymnotiformes, Teleostei), with descriptions of seven subspecies. Zootaxa , 4312 (3): 401-438.
Web links
- Banded knife eel on Fishbase.org (English)