Taxonomy & naming
Parotocinclus jequi was described by Lehmann A., Koech Braun, Pereira and Reis in 2013, in Copeia (volume 2013, number 3, pages 435–440). The Catalog of Fishes (Eschmeyer, CAS) recognises the name as valid (species id 72964).
The species belongs to the subfamily Hypoptopomatinae, the dwarf armoured suckermouth catfishes within Loricariidae, and to Parotocinclus, a large genus distributed across eastern and northern South America.
A key diagnostic feature is the absence of abdominal plates between the pectoral girdle and the anus — a condition shared within the genus only with P. prata and P. robustus. P. jequi is further distinguished by a smaller cleithral width (16.7–20.7% of standard length), a smooth, unwrinkled ventral head surface behind the lower lip in adults, and the absence of dark brown dots on the body.
Morphology
Parotocinclus jequi reaches about 2 in standard length. The body carries the overlapping bony plates characteristic of the family, but the abdomen is notably devoid of dermal plates between the pectoral girdle and the anus.
Fin counts are a single dorsal spine with seven branched dorsal rays and six branched anal rays; the vertebral count is 30–31. The cleithral width is comparatively narrow (16.7–20.7% of standard length). In adults the ventral surface of the head behind the lower lip is smooth and unwrinkled, and the body lacks the dark brown dots seen in some congeners. No data on sexual dimorphism has been published for this species.
Habitat
Parotocinclus jequi is known from the headwaters of the rio Jequitinhonha in eastern Brazil. It inhabits clearwater headwater creeks with depths of about 1–4 ft, over a substrate of rocks and pebbles, with marginal (bank-edge) vegetation present.
Like other members of the genus, it is a facultative air-breather, able to use atmospheric air to supplement gill respiration. No additional water-chemistry measurements beyond the tropical, freshwater, demersal classification have been published.
Feeding
No diet study has been published for Parotocinclus jequi. Members of the genus are generally aufwuchs grazers, rasping the film of algae, diatoms, biofilm and micro-organisms from submerged rocks and pebbles with the suckermouth. The rock-and-pebble substrate of its headwater habitat is consistent with such a grazing habit, but specific dietary data for the species is not available.
Mating
No data on courtship or mating behaviour has been published for Parotocinclus jequi.
Breeding
No reproductive or breeding data has been published for Parotocinclus jequi. The species is not known to have been bred in aquaria.
In the aquarium
Parotocinclus jequi is not established in the aquarium hobby, and no husbandry information has been published for it. Any keeping notes would be inferred from its natural setting rather than documented practice: a small grazer from clear, tropical headwater creeks 1–4 ft deep, over rocks and pebbles with marginal vegetation. Well-oxygenated, clean water with a rock-and-pebble layout and gentle flow would be a reasonable starting point, but the species should be regarded as undocumented in captivity.
Conservation
Parotocinclus jequi was assessed by the IUCN Red List as Least Concern (assessment dated 7 November 2018, per FishBase, version 2025-2). The species is restricted to the headwaters of the rio Jequitinhonha; while it currently carries a Least Concern status, narrowly distributed headwater fishes can be sensitive to local habitat change such as deforestation, water abstraction and sedimentation. No specific threat analysis beyond the Red List status is available here.