Taxonomy & naming
Paralithoxus surinamensis was described by Boeseman in 1982. It was originally placed in the genus Lithoxus; the parentheses around the authority reflect its later transfer to Paralithoxus, the combination accepted by the Catalog of Fishes (Eschmeyer, CAS).
The genus belongs to the subfamily Hypostominae (the Lithoxus group, part of the former Ancistrinae) within the family Loricariidae. Morphological data for the holotype were tabulated by Nijssen & Isbrücker (1990: tab. 1). The specific name refers to Suriname, where the species occurs.
Morphology
Paralithoxus surinamensis is a very small loricariid, reaching only about 1.5 in standard length (SL). The body is strongly depressed (flattened), the form characteristic of the Lithoxus group and adapted to clinging to the substrate in flowing water.
Finer morphological detail is given for the holotype in Nijssen & Isbrücker (1990: tab. 1). No data on sexual dimorphism specific to this species has been published in the sources available here.
Habitat
The species is known from the Gran Rio basin in the upper Suriname River drainage, in Suriname. It inhabits stony rivulets and is a tropical freshwater, demersal fish, its flattened form reflecting life in flowing water over rocky beds.
Detailed water-chemistry measurements for its localities are not published in the sources available here.
Feeding
No data on the diet of Paralithoxus surinamensis has been published in the sources available here. Small benthic members of the Lithoxus group are generally understood to graze biofilm and small invertebrates from rocky surfaces, but specific feeding studies for this species are lacking.
Mating
No data on the courtship or mating behaviour of Paralithoxus surinamensis has been published in the sources available here.
Breeding
No data on the reproduction or breeding of Paralithoxus surinamensis has been published in the sources available here.
In the aquarium
Paralithoxus surinamensis is not established in the aquarium trade, and no husbandry data specific to it has been published in the sources available here. As a tiny, flattened fish of stony rivulets, it would by analogy with related rheophilic loricariids require cool, fast-flowing, highly oxygenated water, but this remains untested for the species.
Conservation
The IUCN Red List assessed Paralithoxus surinamensis as Least Concern (LC), with the assessment dated 20 October 2020 (IUCN Red List version 2025-2). The species occurs in the Gran Rio basin of the upper Suriname River drainage, and the assessment did not identify a level of threat warranting a higher category.