Rhinotocinclus is a genus of suckermouth armored catfish in family Loricariidae, part of the small-bodied Hypoptopomatinae group that also holds Otocinclus and its close relatives. Atlas species are diminutive even by that group's standards, at just 0.5–1 in, and the genus name points to an elongated, rhino-like snout as one of the traits separating it from Otocinclus proper. In the atlas the genus is found in river drainages of Brazil, Colombia, Peru, and Venezuela, in the slow, vegetated margins and leaf-litter habitat typical of small hypoptopomatine plecos, where fine algae and biofilm on submerged wood and leaves make up the diet.
Data on Rhinotocinclus is genuinely thin - all six atlas species carry a Not Evaluated IUCN status, and none show up with a CARES Preservation Program listing, reflecting a genus that has drawn little formal conservation or hobby attention so far. As with other small hypoptopomatine plecos, any aquarium interest would center on their role as unobtrusive algae grazers for soft, gently flowing setups rather than as a showpiece fish, but specific care information for the genus is sparse enough that little can be said with confidence beyond the general pattern shared by its Otocinclus-type relatives.