Taxonomy & naming
Creagrutus gyrospilus was formally described by Richard P. Vari and Adolph S. Harold in their 2001 monograph on the Neotropical characiform genera Creagrutus and Piabina, published in the Smithsonian Contributions to Zoology (volume 613). That work, spanning 239 pages, placed C. gyrospilus within the cis-Andean clade of Creagrutus on the basis of detailed osteological and meristic characters, and listed a type locality in the Venezuelan tributary system draining westward from the Andean cordillera.
The genus Creagrutus belongs to the family Characidae (Eschmeyer's Catalog of Fishes, the governing authority for valid names), a large and ecologically diverse family of Neotropical and African characiforms. Some recent molecular analyses have proposed redistributing certain Creagrutus-allied taxa into Stevardiinae or a provisional Stevardiidae, but Catalog of Fishes continues to place Creagrutus within Characidae, and the family field here follows that authority.
No established common name is recorded for C. gyrospilus in the literature or the hobby trade. The species has not entered the ornamental fish market in any documented form and is known almost entirely from scientific collecting.
Morphology
Creagrutus gyrospilus is a small fish, reaching a maximum standard length of approximately 2.5 in according to FishBase records compiled from the original description and subsequent sampling. Like other members of the genus it is slender and fusiform, adapted for life in fast-flowing currents, with a relatively small head, terminal or slightly inferior mouth, and moderately large eyes.
Creagrutus species in general display subtle but diagnostic differences in scale counts, fin-ray numbers, and the shape of certain bones used in the original Vari and Harold revision to delimit species boundaries. The trophic level recorded for C. gyrospilus is 2.4 — consistent with an insectivore or micropredator feeding low on the food web — and the species is characterised by FishBase as benthopelagic, suggesting it ranges through mid-water and near the substrate rather than being strictly benthic.
Precise coloration data are sparse in the published record. Preserved specimens of Creagrutus typically show a silvery or pale straw ground colour with a lateral stripe of variable intensity and dark pigment on the dorsum; living coloration likely follows this general pattern, though field photographs of C. gyrospilus specifically are not available in accessible sources.
Habitat
Creagrutus gyrospilus occupies clear-water rocky streams and creeks in the central Venezuelan Andes, in tributaries that drain westward and southward into the Santo Domingo River system and ultimately the Apure River, a major tributary of the Orinoco. Recorded localities include streams in the Santo Domingo, Saguaz, Río Claro, Boconó, La Bellaca, and El Molino drainages. The IUCN assessment places the species' extent of occurrence at 14,166 mi² and its area of occupancy at just 25 mi², with six recognised threat-based locations — a distribution that is geographically concentrated and ecologically fragmented.
The IUCN and FishBase both characterise this species as a fast-current stream specialist in rocky Andean tributary habitats. Measured habitat parameters from comparable Orinoco-basin stream biotopes in the region include temperatures around 75 °F, pH in the 5.5–7 range, and low conductivity consistent with soft, moderately acidic upland water over mineral substrates of sand, pebble, gravel, and stones with abundant leaf litter and driftwood. The surrounding landscape is tropical Andean cloud forest and transitional forest, subject to pronounced wet and dry seasons.
Approximately 27 % of the species' range falls within protected areas, including Yacambú National Park, Guaramacal National Park, and Parque Nacional Sierra Nevada. The remaining range is largely unprotected and increasingly affected by habitat conversion.
Feeding
The trophic level of 2.4 recorded for Creagrutus gyrospilus on FishBase indicates a diet composed primarily of small invertebrates, consistent with the feeding habits of other small Creagrutus species in Andean tributary streams. In clear, fast-flowing rocky creeks, available prey would include aquatic insect larvae (chironomids, ephemeropterans, and trichopterans drifting in the current), small crustaceans, and terrestrial invertebrates falling from the riparian canopy.
No dedicated dietary study of C. gyrospilus has been published. The genus name itself — from the Greek for tearing or ripping flesh — alludes to the predatory disposition imputed to Creagrutus historically, although at 2.5 in SL this species takes modest prey. In a comparative Orinoco-basin context, similarly sized characids occupying fast-current streams typically feed opportunistically on drift invertebrates, surface insects, and fine organic material. Aquarium observations of congeners suggest they will accept small prepared foods, but C. gyrospilus is not established in the trade.
Mating
No specific observations of mating behaviour in Creagrutus gyrospilus have been published. By analogy with other small stream-dwelling characids, the species is presumed to be a seasonal open-water egg-scatterer that responds to hydrological cues — rising water levels and shifting temperature at the onset of the wet season — to initiate spawning activity.
Small Creagrutus and allied characids in Andean tributary systems typically congregate in shallower, vegetated margins or over gravel riffles during reproductive periods. Sexual dimorphism, if present, is likely subtle — a slightly fuller abdomen in ripe females being the most common distinguishing feature among congeners. No documented courtship displays or reproductive aggregations have been described for this species.
Breeding
Creagrutus gyrospilus has not been bred in captivity under documented conditions, and detailed reproductive biology data are absent from the primary literature. The reproductive mode inferred for the genus is egg-scattering with adhesive or semi-adhesive eggs deposited among fine-leaved aquatic plants, algal mats, or gravel substrates in fast-flowing sections of stream; no parental care is expected, consistent with the pattern across the Characidae broadly.
Egg incubation period and fry development are undocumented for this species. In fast-current, well-oxygenated streams, eggs of stream-adapted characids typically hatch within a few days at ambient temperatures around 72–79 °F, with larvae initially clinging to the substrate before becoming free-swimming. Data for C. gyrospilus specifically are sparse, and any further detail would require direct field or laboratory observation.
In the aquarium
Creagrutus gyrospilus is not established in the ornamental fish trade and is unknown in home aquaria as a documented species. Its small size (to approximately 2.5 in SL) and fast-current, rocky-stream ecology suggest that, if it were available, it would suit a species-appropriate biotope aquarium replicating a Venezuelan Andean stream: a well-oxygenated tank with moderate to strong flow, a substrate of sand and smooth pebbles, some driftwood and leaf litter, and minimal planting beyond fine-leaved aquatic plants anchored against the current.
Water parameters modelled on its native habitat would target temperatures around 72–79 °F, soft to moderately soft water, and near-neutral to slightly acidic pH. A diet of small live or frozen invertebrates — Daphnia, small bloodworm, and brine shrimp — would suit the inferred feeding ecology. Until the species enters the trade under verified identity, any Creagrutus offered commercially should be verified carefully, as the genus contains numerous similar-looking, geographically distinct species whose captive requirements may differ.
Conservation
Creagrutus gyrospilus is assessed as Vulnerable (VU) on the IUCN Red List under criteria B1ab(iii)+2ab(iii), based on an assessment completed 17 May 2017 and published in 2019. The listing reflects a small and fragmented range — an extent of occurrence of 14,166 mi² and an area of occupancy of only 25 mi² across six threat-based locations — combined with ongoing decline in habitat quality.
The primary documented threats are habitat degradation from agricultural expansion (with approximately 44 % of the surrounding catchment already converted), urbanisation in the foothills of the Venezuelan Andes, and dam construction on the Boconó River and associated waterways. These pressures alter flow regimes, increase sedimentation, and degrade the clear rocky habitats the species requires. Population trend is listed as unknown by the assessors (G. Echevarría; reviewer I.J. Harrison), and no specific recovery plan or targeted monitoring programme is known to be in place.
The partial protection offered by Yacambú, Guaramacal, and Sierra Nevada national parks covers roughly 27 % of the species' range and represents the most significant conservation buffer currently available. Continued enforcement of those protected areas and monitoring of the stream drainages within them would be the most immediately practical conservation measures for this little-studied fish.