Taxonomy & naming
Creagrutus changae was described by Richard P. Vari and Arnold S. Harold in 2001 as part of a large-scale systematic revision of the genus Creagrutus, a speciose assemblage of small characids widespread across tropical South America west of the Andes and in Andean foothill drainages. The valid name, as recorded in Eschmeyer's Catalog of Fishes, is Creagrutus changae Vari & Harold, 2001, and the type locality is in Peru.
The genus Creagrutus belongs to the family Characidae and is among the most species-rich of the western-Andean characid genera, with dozens of recognised species distributed from Venezuela and Colombia south through Ecuador, Peru, and Bolivia. Members of Creagrutus tend to be small, inconspicuous, and superficially similar, making the genus a persistent challenge for field identification; the 2001 revision by Vari and Harold significantly reorganised the group and added numerous new species, including C. changae.
The specific epithet changae honours a person of that name associated with the research; no further biographical details are available from current sources.
Morphology
Creagrutus changae is a small characid with the compact, moderately elongate body plan typical of the genus. Like most Creagrutus, it is a laterally compressed fish with a relatively large eye, a terminal or slightly subterminal mouth, and the characteristic single adipose fin of the family Characidae.
Detailed meristic and morphometric data for C. changae as published in the original 2001 description are not available from current cached sources. As a benthopelagic species it is expected to show adaptations consistent with bottom-oriented foraging — a slightly inferior mouth position and a robust body relative to pelagic characids. Colour in life is not described in current sources; preserved specimens of Creagrutus typically show a pale to silvery body with variable lateral markings, though live colouration is often more vivid.
Size data for this species specifically are not captured in current sources. Congeners span a range of roughly 1–3 in standard length; C. changae is expected to fall within this typical range for the genus, but a confirmed maximum size should be sought from the primary literature before citing a figure.
Habitat
Creagrutus changae is known from the western tributaries of the Ucayali River in the Peruvian departments of Junín, Pasco, and Huánuco — a montane and sub-montane region on the eastern Andean slopes where clear, fast-flowing streams descend toward the lowland Amazon basin. The Ucayali drainage is one of the Amazon's largest sub-systems, and its western headwater tributaries in this region pass through cloud-forest and transitional habitats at varying elevations.
FishBase records the species as freshwater and benthopelagic, indicating a life spent in the lower water column and at or near the substrate of stream channels. Andean foothill streams in this part of Peru are typically cool and well-oxygenated, with clean gravel or rocky substrates and variable amounts of leaf litter. Specific water chemistry parameters for the collection localities of C. changae are not documented in current sources, but the broader Ucayali headwater region is characterised by soft, slightly acidic to neutral water consistent with granitic and metamorphic catchments.
The departments of Junín, Pasco, and Huánuco encompass the central Peruvian Andes and their Amazonian flanks, a zone of exceptionally high freshwater biodiversity that continues to yield new species across multiple groups.
Feeding
FishBase records Creagrutus changae as feeding on detritus, consistent with its benthopelagic habit and its position as a substrate-associated forager in stream habitats. Detritivory — the consumption of decomposing organic matter, biofilm, and associated microorganisms from the stream bed — is a common feeding strategy among small Andean characids inhabiting leaf-litter-rich foothill streams.
Diet studies specific to C. changae are not available in current sources. Congeners and other small detritivorous characids in similar habitats are typically opportunistic, supplementing organic detritus with small invertebrates, algae, and plant material encountered during bottom foraging. In an aquarium context, such species generally accept sinking prepared foods, algae wafers, and frozen or live small invertebrates, though C. changae has not been documented in the hobby trade.
Mating
No published information on the mating behaviour of Creagrutus changae is available in current sources. Based on what is known of closely related small characids in the same genus and family, the species is expected to be an egg-scattering open spawner without parental care — the ancestral and widespread reproductive mode across Characidae.
In this reproductive guild, males typically court females with brief parallel swimming displays or pursuit behaviour, and spawning involves the simultaneous release of eggs and milt into open water or among fine substrate and vegetation. Adhesive or semi-adhesive eggs settle among gravel or leaf litter and receive no further attention from either parent. Specific details of courtship, male secondary characters, or spawning triggers for C. changae await observation of the species in the field or captivity.
Breeding
Creagrutus changae has not been bred in captivity under documented conditions, and no breeding data are available from current sources. The general breeding biology assumed for the genus follows the typical small-characid pattern: adhesive or non-adhesive eggs scattered over fine substrate or vegetation, with no parental care and a short incubation period sensitive to water temperature.
For context, small Andean-foothill characids of similar size and habitat tend to produce relatively small clutches of eggs that hatch within two to five days at warm temperatures, with free-swimming larvae requiring very small first foods such as infusoria or rotifers before transitioning to newly hatched brine shrimp. These parameters are informed inferences from the broader family and genus, not confirmed data for C. changae specifically; breeding records from kept specimens would be a genuine contribution to knowledge of the species.
In the aquarium
Creagrutus changae is not established in the aquarium trade and is essentially unknown to hobbyists. It has not been exported from Peru commercially in any quantity, and there are no care guides, community reports, or breeding accounts specific to this species in available sources.
Based on the biology of the genus, C. changae would likely do best in a well-filtered, moderately cool aquarium with clean, soft to neutral water, some water movement, and a substrate of fine gravel or sand with leaf litter. A diet of sinking prepared foods supplemented with small live or frozen invertebrates would suit its detritivorous and substrate-oriented habits. Any aquarist fortunate enough to obtain specimens from a specialist importer would be working in essentially undocumented territory, and records of behaviour, diet acceptance, and successful breeding would be valuable to the scientific and hobby communities alike.
Conservation
Creagrutus changae is assessed as Least Concern (LC) on the IUCN Red List, with the assessment recorded as of 2014. The Least Concern status reflects that the species is not currently considered to meet the thresholds for a threatened category, though it is a narrow-range endemic confined to a specific sub-region of the Peruvian Andes — the western Ucayali tributaries in Junín, Pasco, and Huánuco.
The broader Andean foothill zone of central Peru faces ongoing pressures from deforestation, agricultural expansion, mining, and associated sedimentation and water quality degradation in freshwater systems. Many narrow-range Andean stream fishes occupy small catchments with limited dispersal capacity and could be disproportionately affected by local habitat loss. No specific population data or threat assessments are available for C. changae beyond the IUCN status designation, and the 2014 assessment may not fully reflect current conditions. Ongoing monitoring of headwater stream habitats in Junín, Pasco, and Huánuco would be prudent given the vulnerability of endemic Andean ichthyofauna to land-use change.