Paralithoxus is a genus of small, flattened suckermouth catfish in the pleco family, restricted to Guiana Shield river systems in northeastern South America, spanning French Guiana, Suriname, Guyana, and adjacent Brazil. Like other small hypoptopomatine plecos, its species are built to cling to rock and cobble in fast, well-oxygenated rapids, grazing algae and biofilm from stone surfaces with a sucker-like mouth. At 1.5–3 in, they rank among the smallest plecos covered in the atlas.
Paralithoxus is essentially a genus of scientific rather than hobby interest: its species are narrow-range endemics of remote, fast-flowing Guiana Shield streams and rarely, if ever, reach the aquarium trade. Their small size and algae-grazing habits would in principle suit a strong-current, well-oxygenated biotope setup, but hobbyist experience with the group is negligible and husbandry data are sparse. The IUCN picture is mixed, with Near Threatened and Least Concern species both represented, consistent with restricted ranges rather than one acute, genus-wide threat.