Otothyropsis is a genus of diminutive armored catfish in family Loricariidae, placed among the small algae-grazing plecos of subfamily Hypoptopomatinae alongside Otocinclus and Otothyris, from river drainages of Brazil and Paraguay. Atlas species are tiny even by that group's standards, 1–1.5 in, with the flattened, bony-plated body and ventral suckermouth of the family scaled down to a size closer to a large Otocinclus than a typical pleco - built for gripping surfaces in current and rasping algae and biofilm rather than wood or driftwood.
This is a genus known mainly to specialist loricariid taxonomists and dedicated small-pleco keepers rather than the general aquarium trade, and individual species such as O. piribebuy (black oto) turn up only occasionally in specialist channels; care where it is kept broadly follows the gentle-current, algae-forward approach used for Otocinclus. Conservation status is reassuring across the genus - five of the six atlas species are assessed Least Concern, with only one Not Evaluated - though as with many small South American stream loricariids, formal assessment has generally followed well behind the pace of new species descriptions in this group.