Eigenmannia

{{Short description|Genus of fishes}}

{{Automatic taxobox

| image = Eigenmannia virescens 000.jpg

| image_caption = Eigenmannia virescens

| taxon = Eigenmannia

| authority = D. S. Jordan & Evermann, 1896{{Cof family|family=Sternopygidae|access-date=28 May 2025}}

| type_species = Sternopygus humboldtii

| type_species_authority = Steindachner, 1878

| synonyms = * Cryptops Eigenmann, 1894

| synonyms_ref =

}}

Eigenmannia is a genus of fish in the family Sternopygidae (glass knifefishes) native to tropical and subtropical South America (south to the Río de la Plata Basin), and Panama.{{FishBase genus | genus = Eigenmannia| month = August | year = 2019}}Peixoto, L.A.W., Dutra, G.M. & Wosiacki, W.B. (2015). The Electric Glass Knifefishes of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species. Zoological Journal of the Linnean Society, 175 (2): 384–414. They are typically found in slow-flowing streams, along the edge of large rivers, in deep river channels and in floodplains, and the genus also includes E. vicentespelaea, the only cave-adapted knifefish.{{cite book | editor1=van der Sleen, P. | editor2=J.S. Albert | year=2017 | title=Field Guide to the Fishes of the Amazon, Orinoco, and Guianas | publisher=Princeton University Press | pages=343–344 | isbn=978-0691170749 }} Eigenmannia are often found near submerged roots, aquatic plants and floating meadows.{{cite journal| author1=Carvalho, L.N. | author2=L. Fidelis | author3=R. Arruda | author4=A. Galuch | author5=K. Zuanon | year=2013 | title=Second floor, please: the fish fauna of floating litter banks in Amazonian streams and rivers | journal=Neotrop. Ichthyol. | volume=11 | issue=1 | pages=78–91 | doi=10.1590/S1679-62252013000100010 | doi-access=free }}

Depending on the exact species, they have a maximum total length of {{convert|14.3-49.6|cm|in|abbr=on|0}}. They are nocturnal, and feed on small invertebrates such as aquatic insect larvae and zooplanktonic crustaceans.