Caenotropus is a genus of headstanders in family Chilodontidae, close relatives of the more familiar Chilodus, found across the Guiana Shield and northern Amazon drainages - the atlas's 4 species are recorded from Brazil, Suriname, Venezuela, Colombia, French Guiana, and Guyana. As the common name suggests, these fish habitually swim at a steep, head-down angle, using a small, downward-oriented mouth to graze algae, detritus, and periphyton off submerged wood, leaf litter, and rock surfaces. Atlas species range from about 3.5–7.5 in, elongate-bodied with the slim profile typical of the family.
Species such as the headstander (C. labyrinthicus) and spotted headstander (C. maculosus) turn up occasionally in the aquarium trade, valued by specialist keepers for their unusual posture and algae-grazing behavior in planted or driftwood-heavy tanks rather than for bright color. Conservation data are incomplete - two species assessed Least Concern and two Not Evaluated - consistent with a genus that draws less survey attention than the region's showier characins.