Neoplecostomus is a genus of suckermouth armored catfish in the family Loricariidae, endemic to Brazil, where the atlas's 17 species are confined to cool, fast-flowing upland streams and headwaters of the southeastern coastal drainages and the upper Paraná system. Species run a modest 3–4.5 in and share the loricariid body plan — a flattened, bony-plated body with a ventral sucker mouth for grazing algae and biofilm off rock — but Neoplecostomus differs from many of its relatives in favoring cooler, well-oxygenated, high-gradient water rather than warm lowland rivers, and in generally lacking the interopercular cheek odontodes (bristle-like spines) that mark related genera such as Hisonotus and Pareiorhaphis.
Neoplecostomus is of far more scientific than aquarium interest: it rarely appears in the hobby trade, and most of what is documented about the genus comes from taxonomic and biogeographic survey work rather than aquarist accounts. Its restricted, headwater-stream distribution makes individual species vulnerable to local habitat disturbance, and the atlas's IUCN tally includes species rated Critically Endangered and Endangered alongside a majority of Least Concern, with several still Not Evaluated or Data Deficient — a pattern typical of a genus whose species are each confined to a small number of streams in a heavily developed part of Brazil.
The genus has been the subject of active taxonomic revision, with several of its currently recognized species described only in the past two decades as researchers worked through Loricariidae material from previously under-sampled Brazilian coastal drainages; species-level boundaries within the group are still being refined.