Taxonomy & naming
Curculionichthys scaius was described by Calegari, Gamarra and Reis in 2018. It is placed in the subfamily Hypoptopomatinae within Loricariidae, in the genus Curculionichthys (erected in 2015).
The Catalog of Fishes (Eschmeyer, CAS) is the authority for valid names. The authority is Calegari, Gamarra & Reis, 2018 — not Roxo, Ochoa, Silva & Oliveira, 2018; that team described a different Curculionichthys from the eastern Guiana Shield in Suriname. C. scaius is the Calegari, Gamarra & Reis species, as confirmed by the FishBase CoF-derived authority file.
Morphology
Curculionichthys scaius is a very small loricariid, reaching about 1 in standard length. As in its congeners, the genus name reflects the elongated, weevil-like snout (Latin 'curculio') combined with Greek 'ichthys' (fish). The body bears the armoured plates and ventral suckermouth typical of the Hypoptopomatinae. Diagnostic detail distinguishing it from related species is provided in the original 2018 description; it is not summarised further in the secondary sources consulted.
Habitat
The species occurs in South America — Brazil, in westerly drainages of the Brazilian Shield. It is a freshwater, demersal fish recorded at shallow depths of roughly 0–3 ft in tropical waters. Detailed water-chemistry data for its localities are not published in the available sources.
Feeding
Diet is not specified in the available sources. Hypoptopomatines are generally small grazers of biofilm and algae, but no feeding study specific to Curculionichthys scaius has been published, so its diet remains undocumented.
Mating
No data on courtship or mating behaviour have been published for Curculionichthys scaius.
Breeding
No data on reproduction, spawning mode, clutch size, or parental care have been published for this species.
In the aquarium
Curculionichthys scaius is not a species of the ornamental trade and is essentially unknown in aquarium keeping. No husbandry information is published, and none is offered here to avoid speculation.
Conservation
Curculionichthys scaius has not been evaluated by the IUCN Red List (Not Evaluated). As a recently described, small-bodied Brazilian Shield endemic, no conservation assessment or species-specific threat data are currently available.