Porotergus is a genus of weakly electric knifefish in the family Apteronotidae, the ghost knifefishes, distributed across slow, structure-rich rivers and flooded forest habitat in Brazil, Peru, French Guiana, Guyana, Argentina, Bolivia, and Suriname. The atlas covers 7 species ranging from about 4.5 in up to 15 in. Like its relatives, the genus shares the classic apteronotid body plan: an elongated, laterally compressed body that tapers to a whip-like tail with no true caudal fin, swimming powered mainly by a long anal fin that runs most of the body's underside, and no pelvic fins at all. A weak electric organ discharged continuously from specialized tissue lets these fish navigate and communicate in dark, often turbid water where vision is of limited use.
Porotergus draws far less aquarium attention than its famous relative the black ghost knifefish (genus Apteronotus), and most species, including P. ellisi (Ellis's ghost knifefish), are more a subject of ichthyological and electric-fish research interest than mainstream trade. Where the genus does turn up in the hobby it is treated much like other knifefish, as a nocturnal, secretive bottom- and midwater-forager needing plenty of cover and calm tankmates. IUCN status leans Least Concern where assessed, with a few species still Not Evaluated or Data Deficient, consistent with a genus that is widespread but not intensively studied outside specialist electric-fish research.