. . . . . . "Potamotrygon is a genus of freshwater stingrays native to the rivers of South America.Freshwater stingrays of the genus Potamotrygon are sometimes kept as exotic aquarium fish; though freshwater stingray of other genera do appear in the trade, most are from this genus. They are best kept with a deep, sandy substrate, in which they bury themselves, often with only the eyes visible."@en . . .