Sternarchella is a genus of ghost knifefish in the family Apteronotidae, weakly electric fish that generate a continuous electric field from a specialized tail organ and use it for orientation and communication in the dark, sediment-rich channels of northern South America. The atlas covers 10 species, from about 6.5 in up to over 15.5 in, found across Brazil, Peru, Colombia, Venezuela, Bolivia, and Ecuador in the Amazon and Orinoco drainages. Like other apteronotids, Sternarchella lack a true dorsal fin and instead propel themselves with a long, ribbon-like anal fin that lets them swim forward and backward with equal ease, a useful trick for animals that spend much of their time nosing along riverbeds and among submerged wood.
None of the ten species are established aquarium fish; Sternarchella is essentially a genus of scientific interest, encountered mainly in ichthyological surveys and, occasionally, specialist imports rather than the general trade, unlike its better-known relative, the black ghost knifefish. Sternarchella raptor, the bulldog knifefish, is presumably named for its heavy, blunt-jawed head. With six of the ten species rated Least Concern and three Data Deficient, the genus reads as broadly distributed through major river channels but still under-surveyed, typical for deep-water, nocturnal Amazonian fish, and the atlas carries no CARES-listed species here.