Sternarchorhynchus is a genus of weakly electric knifefishes in the family Apteronotidae, distinguished by a long, tubular, downturned snout that gives the group its common name of tube-snouted ghost knifefish. Species occur through major South American river systems, with the brief's records spanning Brazil, Peru, Venezuela, Colombia, Ecuador, and the Guianas. Like other apteronotids they lack a distinct tail fin, swim by undulating a long anal fin, and generate a weak electric field they use to navigate and locate prey in dark water and among submerged structure rather than to stun anything. The atlas covers 33 species with a wide size range, from around 5.5 in to species that reach roughly 23.5 in, and the elongated snout is thought to help them probe crevices, sand, and detritus for buried invertebrates.
The genus is mostly of scientific rather than aquarium interest: unlike its relative Apteronotus, Sternarchorhynchus is rarely if ever offered in the ornamental fish trade, and many of its species have been described only in the last few decades, which shows up in the atlas's IUCN tally as a large share of Not Evaluated and Data Deficient listings. Where assessments exist they skew more concerning than most freshwater fish genera, with several species rated Vulnerable, Endangered, or Critically Endangered, reflecting narrow river-reach ranges and the pressure of damming and habitat change across Amazonian and Orinoco drainages. Their nocturnal, bottom-oriented habits in deep river channels also make them poorly surveyed, so the true number of species and their real conservation status likely remain incompletely known.