Pareiorhina is a genus of small suckermouth catfish, family Loricariidae, endemic to Brazil, where its species occupy small, clear headwater streams rather than the larger rivers favoured by many of their relatives. They are among the smallest loricariids in the atlas, most adults topping out between about 3.5 and 2 in, with the flattened head, armoured body, and sucker mouth typical of the family scaled down to fit a life spent gripping stones in shallow, fast-flowing water.
Pareiorhina is largely a genus of scientific rather than hobby interest; only the species Pareiorhina rudolphi carries a common name in the atlas — cascudinho, Portuguese for 'little armoured catfish' — and none of the eleven species are widely traded. Where they do appear, their tiny size and current-loving habits suit dedicated nano or biotope streamside setups rather than general community tanks. Conservation data are limited: several species are not evaluated, but three are listed Near Threatened, a reminder that small, single-drainage Brazilian endemics can be vulnerable to localised habitat change despite a thin formal conservation record.