''Gymnorhamphichthys'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of South American sand knifefishes found in the

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

, Araguaia,

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

and

Río de la Plata The Río de la Plata (; ), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda, Colonia, Punta Gorda. It empties into the Atlantic Ocean and ...

basins, as well as rivers in the

Guianas The Guianas, also spelled Guyanas or Guayanas, are a geographical region in north-eastern South America. Strictly, the term refers to the three Guianas: Guyana, Suriname, and French Guiana, formerly British Guiana, British, Surinam (Dutch colo ...

. They inhabit both small streams and large rivers, but usually over a sandy bottom. During the night they swim head-down over the sandy bottom to locate small invertebrate prey like insect larvae and during the day they rest buried under the sand. They are generally very pale (almost whitish, light silvery, light yellowish or semi-translucent), and have a pattern of dark bars/spots or a dark line along the side of the body. Their snout is relatively long, thin and tubular. ''Gymnorhamphichthys'' are small knifefish with the largest species reaching up to about in total length.

Species

These are the currently recognized species in this genus:

References

Rhamphichthyidae Freshwater fish of South America Freshwater fish genera Taxa named by Max Mapes Ellis {{Gymnotiformes-stub