Aphanotorulus is a genus of armored suckermouth catfish in the pleco family Loricariidae, native to Amazonian and Orinoco drainages of South America. The atlas covers 7 species, sized from about 4 in to 14 in, with records spanning Brazil, Peru, Ecuador, Venezuela, Bolivia, Colombia, and Guyana. Like other loricariids they carry rows of bony armor plates instead of scales and a ventral sucker-mouth used to grip rocks and wood in current, and several species in the genus favor sandy or fine-sediment river bottoms rather than the rockier habitats typical of many plecos, feeding by sifting detritus and algae from the substrate.
A handful of Aphanotorulus species circulate in the pleco hobby, generally as specialist rather than mainstream fish — Aphanotorulus ammophilus (cute pleco) and A. emarginatus (red fin thresher pleco) are the most recognizable by their trade names, while A. horridus (bristly pleco) is named for its unusually bristly body. Their sand-sifting habits mean they do best over a fine, soft substrate rather than gravel, which can abrade their undersides. Conservation-wise the genus reads as reasonably secure — four of the seven atlas species are Least Concern — though two are Data Deficient, a reminder that even reasonably well-collected Amazonian catfish genera can have real gaps in population data.