Rhinelepis is a genus of large armored catfish (family Loricariidae, subfamily Hypostominae) from the Parana-Paraguay river system of southern South America, with the atlas's records spanning Argentina, Brazil, Paraguay, and Uruguay. Its two species, R. aspera and R. strigosa, are big-bodied plecos by hobby standards, reaching roughly 19–19.5 in, with the typical loricariid armor of overlapping bony plates, a ventral sucker-mouth adapted for rasping algae and biofilm from rock and wood surfaces, and a robust, torpedo-shaped build suited to life in the strong current of large rivers.
R. aspera, widely known in the trade as the Black Rhino Pleco, is the more familiar of the two, valued both as a large, hardy algae-eating tankmate and, in parts of its native range, as a food fish -- populations in the Parana basin are known to undertake spawning migrations upriver, a behavior documented in several large South American loricariids. Conservation status is comparatively reassuring for the genus, split between Near Threatened and Least Concern, though large migratory river fish of this kind remain sensitive to dam construction and the loss of free-flowing river reaches.