Hypophthalmus marginatus, commonly called the Mapará, is a species of demersal potamodromous catfish of the family Pimelodidae that is native to Amazon and Orinoco River basins of Brazil, Peru and major rivers of French Guiana and Suriname.
It grows to a length of .
A parasite of the esophageal musculature, Kudoa amazonica was found from the fish.