Taxonomy & naming
Paralithoxus boujardi was described by Muller and Isbrücker in 1993, originally in the genus Lithoxus. It was subsequently transferred to Paralithoxus, the combination recognised as valid by the Catalog of Fishes (Eschmeyer, CAS). Le Bail et al. (2000:242) provide a complementary description together with notes on its biology and distribution.
The species belongs to the subfamily Hypostominae — specifically the Lithoxus group within the tribe Ancistrini — the large subfamily that contains most of the bristle-bearing and armoured plecos. The Lithoxus/Paralithoxus lineage comprises small, strongly depressed (flattened) loricariids adapted to clinging in swift water.
The specific epithet boujardi honours Dr Thierry Boujard, a hydrobiologist, ichthyologist and physiologist.
Morphology
Paralithoxus boujardi reaches about 2.5 in in standard length. As a member of the Lithoxus group it has the strongly dorsoventrally flattened, low-profile body typical of fast-water loricariids — a form that minimises drag and lets the fish hold position on rock in strong current using its ventral suckermouth. Detailed colour and meristic data beyond the original description and Le Bail et al. (2000) were not available in the sources consulted, so finer morphological specifics are not elaborated here.
Habitat
The species is endemic to the Approuague and Oyapock river basins of French Guiana. It is a freshwater, demersal, tropical fish that frequents the fast-flowing waters of the principal rivers and their creeks, where the substrate is rock or sand. Like others in its genus it is a facultative air-breather, a genus-level trait that suits life in warm, turbulent waters where dissolved oxygen can fluctuate.
Specific measured water parameters (temperature, pH, hardness) were not detailed in the available sources, so no precise field chemistry is published here beyond the description of swift, rocky-and-sandy river habitat.
Feeding
No diet study specific to Paralithoxus boujardi has been published. Small rheophilic loricariids of this group are generally grazers of the biofilm — algae, diatoms, and associated micro-invertebrates — coating rocks in fast water, taken with the suckermouth. A comparable habit is plausible for this species, but it is noted here as an expectation drawn from the genus rather than a documented observation for P. boujardi.
Mating
Courtship and mating behaviour of Paralithoxus boujardi have not been documented in the sources consulted. No observations of pairing or spawning-site behaviour are available.
Breeding
No reproductive biology — clutch size, spawning mode, or parental care — has been published for Paralithoxus boujardi. Sexual dimorphism for this species was not detailed in the available sources, so no statement on male/female differences can be made here.
In the aquarium
Paralithoxus boujardi is not an established aquarium fish, and no husbandry or trade information is available for it. As a small, current-loving rheophile it would in principle require cool, fast-flowing, highly oxygenated water with a rock-and-sand substrate to thrive — but no specific captive-care guidance is published, and none should be inferred beyond these general habitat requirements.
Conservation
The IUCN Red List assessed Paralithoxus boujardi as Near Threatened in 2020, under criterion B1ab(iii) — reflecting a restricted range (the Approuague and Oyapock basins of French Guiana) combined with a continuing decline in habitat quality, though not yet meeting the thresholds for a fully threatened category. As a rheophilic species dependent on clear, fast-flowing, rocky river habitat, it is sensitive to flow alteration, sedimentation, and water-quality degradation. Continued monitoring of its limited range is warranted; no species-specific conservation measures are documented.