The Elephant-nose Knifefish, (Sternarchorhynchus retzeri), is a species of electric
fish found in South America. Sternarchorhynchus retzeri is broadly
distributed across the Amazon basin from the Rio Iça basin in the western portions
of Amazonas, Brazil, to the Rio Trombetas in Pará, Brazil. Elephant-nose Knifefish
live along the bottoms of rivers, actively preying on benthic invertebrates, including
insect larvae. Sternarchorhynchus retzeri have electrogenic abilities using the
electric field generated to aid in the location and capture of prey living in the mud
and leaf litter and other detritus. Their long snout aids in the capture of prey hiding
in small crevices on the river floor. Their electrogenic abilities are also used for
electrocommunication (De Santana and Vari 2010).
Elephant-nose Knifefish are laterally compressed, with an elongated snout. The
snout is generally straight, though it may have has a slight downward curve.
Individuals of this species range between 300 and 400 mm, with females generally
being larger than the males. Sternarchorhynchus retzeri have dark pigmentation that
generally reflects the surrounding environment (De Santana and Vari 2010). Anal and pectoral fins tend to be darker at the ends than the rest of the body (De Santana and Vari 2010).