Steatogenys is a genus of weakly electric knifefish in the order Gymnotiformes, widespread across Amazon and Orinoco basin drainages - the atlas records it from Brazil, Peru, Venezuela, Colombia, Ecuador, French Guiana, Guyana, and Suriname. Like other gymnotiforms, it has an elongated, laterally compressed body with no dorsal or pelvic fins, swimming by undulating a long anal fin, and generates a weak electric field from a specialized organ for electrolocation and communication in dark or turbid water. Atlas species run 8–16 in.
These are nocturnal, secretive fish, active mainly after dark and sheltering by day among submerged wood, roots, and leaf litter. They are mostly of scientific rather than hobby interest - unlike the far more familiar black ghost knifefish, Steatogenys species rarely appear in the aquarium trade, though the centipede knifefish (S. duidae) and elegant knifefish (S. elegans) are occasionally available to specialist keepers willing to provide dim, current-rich, driftwood-furnished tanks. Conservation looks stable where assessed, matching the brief's tally of 2 Least Concern and 1 Not Evaluated.