Taxonomy & naming
Hypostomus velhochico was described by Zawadzki, Oyakawa and Britski in 2017 in Zootaxa (volume 4344, number 3, pages 553–567). The holotype (MZUSP 47327, 3.5 in SL) was collected from a small stream tributary of the rio Itacarambi, itself a tributary of the rio São Francisco, near São João das Missões, Minas Gerais, Brazil. Paratypes ranged from 3–3.5 in SL. The Catalog of Fishes (Eschmeyer, CAS) recognises the species as valid within Hypostomus Lacépède, 1803.
The species is distinguished from its congeners by a combination of characters: slender bicuspid teeth, dentaries angled more than 90°, conspicuous keels along the lateral series of plates, small roundish dark spots aligned along the lateral plate series, and a single plate bordering the supraoccipital. These characters separate H. velhochico from all other Hypostomus known from the São Francisco basin. The species falls within the subfamily Hypostominae of the family Loricariidae.
Morphology
Adults reach a maximum of approximately 5.5 in standard length (SL), making H. velhochico a small Hypostomus. The species' most distinctive external character is the presence of conspicuous keels — raised ridges — along the lateral series of plates, giving the flanks a sharply ridged profile that is absent or much reduced in most congeners. The overall body plan follows the typical loricariid template: depressed, armoured with interlocking bony scutes, with a broad, ventrally placed suctorial mouth.
Coloration features small, roundish dark spots arranged in alignment along the lateral plate series — a neat, ordered pattern that contrasts with the more randomly distributed or absent spotting of many congeners. The dentition consists of slender bicuspid teeth, with the dentaries forming an angle of more than 90°. A single plate bordering the supraoccipital is a further meristic character used in diagnosis. Sexual dimorphism has not been specifically described; as in Hypostomus generally, breeding males may develop odontodes on the pectoral spine and snout.
Habitat
Hypostomus velhochico is distributed across multiple subbasins of the rio São Francisco — one of Brazil's longest rivers, draining the semi-arid interior of the country and flowing ultimately into the Atlantic Ocean in Alagoas and Sergipe. Records span Minas Gerais, Bahia, and the Distrito Federal, encompassing tributaries such as the rio Cipó (Minas Gerais), the rio Preto (tributary of the rio Paracatu, Distrito Federal), the rio Verde Grande, and the rio Coxá (both draining into the Sobradinho reservoir area, Bahia).
FishBase records indicate the species inhabits low-current stretches with sandy-clay substrate, in rivers approximately 66 ft wide and 3–7 ft deep, within the Cerrado biome. Riparian Cerrado vegetation characterises these reaches. This is a different ecological setting from the large rocky rapids favoured by some Hypostomus: H. velhochico is a fish of calmer, shallower, substrate-rich headwaters and mid-basin tributaries rather than swift mainstem channels. Like all Hypostomus, it is a facultative air-breather, a useful adaptation in the São Francisco basin where water levels and oxygen conditions can fluctuate seasonally.
Feeding
Diet has not been specifically studied for Hypostomus velhochico. Its dentition — slender bicuspid teeth rather than the broad spoon-shaped teeth of the cochliodon group — suggests a diet more characteristic of generalist Hypostomus: aufwuchs grazing (algae, diatoms, periphyton, and biofilm) scraped from rocky or clay substrates, supplemented by fine detritus and organic sediment. The sandy-clay habitat noted for the species is consistent with a scavenging and grazing feeding mode rather than xylivory.
In captivity, the species would be expected to accept the standard large-suckermouth diet: algae wafers, sinking pellets, blanched vegetables (courgette, cucumber, sweet potato), and spirulina-based foods, with driftwood available for supplemental rasping even if it is not a primary dietary component.
Mating
No information on mating behaviour has been published for Hypostomus velhochico. In the genus, courtship follows a pattern in which males hold and advertise suitable spawning sites — burrows, crevices, or woody cavities — while competing with rival males, often through agonistic displays involving erect fin spines and pectoral-spine odontodes.
For a small Hypostomus in a wide-ranging São Francisco distribution, breeding likely coincides with seasonal rainfall patterns that raise river levels and temperature, as is typical for loricariids throughout the Neotropical region.
Breeding
No captive breeding records have been located for Hypostomus velhochico. By analogy with other members of the genus, a cave-spawning strategy is expected: the male defends a burrow or crevice, the female deposits adhesive eggs on the cavity walls, and the male provides paternal care — fanning the eggs to maintain oxygenation and removing infertile eggs — through an incubation period of approximately five to seven days at tropical temperatures. Fry emerge as miniature adults, already armoured, and begin grazing rapidly.
For a species at roughly 5.5 in SL, clutch sizes in Hypostomus typically number in the dozens to low hundreds, though no data specific to H. velhochico have been published.
In the aquarium
Hypostomus velhochico is not a species currently available in the ornamental fish trade. Its modest adult size — under 5.5 in SL — makes it among the more aquarium-manageable Hypostomus, comparable in scale to species that are occasionally kept by Loricariidae enthusiasts. A tank of 40–55 US gal would be appropriate for a single adult, furnished with sandy or fine-gravel substrate, some rock structure, and pieces of driftwood.
Given the São Francisco origin, water parameters should reflect a moderately warm, well-oxygenated tropical system. The Cerrado rivers of the São Francisco basin can span a range of chemistries; soft to moderately hard, neutral to slightly alkaline water (pH 6.8–7.5, temperatures 72–81 °F) is a reasonable first approximation, though no field measurements specific to this species' collection sites have been published.
Should this species ever enter the trade — whether through targeted collection or captive breeding — it would suit a quiet community of non-aggressive mid-water fish. Its preference for low-current environments means it does not require a strong powerhead or high-flow filtration beyond that necessary for water quality.
Conservation
Hypostomus velhochico was assessed as Least Concern by the IUCN Red List on 2 December 2020. Its range is wide relative to many São Francisco endemics, spanning multiple subbasins in Minas Gerais, Bahia, and the Distrito Federal, with no major threats to the overall population identified at the time of assessment.
The rio São Francisco basin as a whole faces substantial pressure: deforestation of Cerrado riparian margins, agricultural water extraction, pollution, and the effects of the Sobradinho reservoir — one of the world's largest artificial lakes — on downstream hydrology and sediment dynamics. Although H. velhochico has been recorded from tributaries near the Sobradinho reservoir area, the species appears sufficiently widespread across multiple subbasins that reservoir effects alone are unlikely to threaten it at the species level. Continued baseline monitoring of its populations across the basin is nevertheless valuable given the ongoing transformation of the São Francisco watershed.