Cordylancistrus is a genus of armored suckermouth catfish in the pleco family Loricariidae, restricted to river systems in Colombia and Venezuela — the atlas's 7 species are recorded from those two countries alone. Sized from about 2.5 in to 6 in, most species inhabit upland and piedmont streams of trans-Andean drainages such as the Magdalena and Maracaibo basins rather than the lowland Amazon habitats typical of many South American plecos. Like other ancistrine loricariids, they have a flattened, bristled head and body covered in bony plates, and cling to rocks in flowing water using a ventral sucker-mouth, grazing algae and biofilm from stone surfaces.
The genus is more a subject for pleco specialists and taxonomists than the mainstream aquarium trade, with most species — including Cordylancistrus daguae, C. nephelion, C. perijae, C. pijao, C. setosus, and C. tayrona — known mainly from scientific collections rather than regular commercial supply; C. torbesensis (Torbes pleco) is one of the few to carry an established trade name. Because many species are confined to single river drainages in a relatively small geographic area, the genus carries real conservation concern: the atlas lists one species as Endangered and another as Near Threatened alongside a mostly Not Evaluated backdrop, a pattern typical of narrow-range Andean stream fish vulnerable to habitat degradation and water extraction.