Taxonomy & naming
Chrysobrycon myersi was described by Stanley H. Weitzman and James E. Thomerson in 1970 in the Proceedings of the California Academy of Sciences under the name Hysteronotus myersi, designated as a new species of glandulocaudin characid from Peru. The type locality is a tributary of the Pachitea River northeast of Tournavista, Huanuco Province, in the Peruvian Amazon. Subsequent revisions transferred the species to the genus Chrysobrycon, which belongs to the tribe Stevardiini within Characidae. Eschmeyer's Catalog of Fishes treats the valid name as Chrysobrycon myersi (Weitzman & Thomerson, 1970), with parenthetical authority indicating the change of genus since the original description.
Chrysobrycon is a moderately small genus of characids whose members share glandular tissue associated with the caudal fin in males — a feature of the broader glandulocaudine assemblage that was long treated as a subfamily and is now embedded within Stevardiini. The genus name is formed from the Greek chrysos (golden) and the root ebryko (to bite or gnaw), a combination that appears to reference physical characters of the jaw or dentition.
Morphology
Chrysobrycon myersi reaches a maximum recorded standard length of 2.5 in, placing it at the smaller end of the size range for the genus. Like other stevardiine characids, it is a slender, fusiform fish with the characteristic large eye and silver-flanked body common to small Amazonian tetras. Specific detailed morphological descriptions in the accessible literature are sparse, and the original 1970 description remains the primary reference for characters such as scale counts, fin ray formulae, and dentition.
Males in glandulocaudin groups typically bear modified scales or glandular tissue near the caudal fin that functions in reproductive signalling, and this feature is likely present in C. myersi as in its congeners, though no published account in the available sources details it for this species specifically. Sexual dimorphism in body proportions and colouration has not been described in accessible sources.
Habitat
Chrysobrycon myersi inhabits streams and rivers of the Ucayali drainage in the Peruvian Amazon, with documented records from the Pachitea, Urubamba, and Tambo river basins at elevations of approximately 850–1919 ft above sea level. The type locality is a tributary of the Pachitea River in Huanuco Province. The IUCN assessment describes the species' habitat as rainforest streams with abundant vegetation and clear to moderately dark waters.
The upper Ucayali region encompasses Andean foothill streams that typically carry soft, slightly acidic to neutral water draining through forest soils, though conditions vary with catchment geology and seasonal flood pulses. The IUCN assessment notes a threat from illegal gold mining in the lower Pachitea River, which can introduce sedimentation and heavy-metal contamination into tributary systems. No detailed microhabitat description — substrate type, depth preference, or current preference — has been published in the accessible literature for this species.
Feeding
FishBase assigns Chrysobrycon myersi a trophic level of 3.0 and lists it as a freshwater pelagic species, suggesting it feeds in the open water column on invertebrates or small particles rather than grazing primarily on benthic material. Glandulocaudin and stevardiine characids as a group tend toward omnivory, taking small aquatic invertebrates, zooplankton, and occasionally plant material or algae in proportion to availability.
No species-specific feeding study or stomach-content analysis has been published in the accessible literature for C. myersi. In an aquarium context, the species would be expected to accept small live and frozen invertebrates such as Daphnia, Artemia nauplii, and mosquito larvae, as well as quality fine-particle prepared foods, based on the feeding habits common to small Amazonian tetras of comparable size and ecology.
Mating
No published study has documented the mating behaviour of Chrysobrycon myersi in the field or in controlled conditions. Within the stevardiine and glandulocaudin clade, males typically possess specialised structures — modified scales or hook-bearing anal fin rays — that play a role in courtship signalling or physical contact with females during spawning. The genus Chrysobrycon is part of this broader assembly, so analogous male display structures are plausible though not confirmed for this species in the sources available.
By analogy with related open-spawning characids of comparable size and ecology, courtship likely involves male pursuit and lateral display near dense vegetation or cover. The comparative scarcity of breeding observations in the literature reflects both the species' restricted distribution and its rarity in the hobby.
Breeding
No species-specific breeding account for Chrysobrycon myersi has been recorded in the available sources. The broader Stevardiini tribe includes egg-scattering species that deposit adhesive or non-adhesive eggs among fine-leaved vegetation without providing parental care — a pattern consistent with most small Amazonian characids. Whether C. myersi follows this mode precisely, or shows the derived internal fertilisation that some stevardiine genera (notably Corynopoma and allies) have evolved, has not been documented in accessible literature.
In captivity, any attempt to breed the species would logically begin with soft, slightly acidic water reflecting the Andean foothill streams of its natural range, a conditioning period with live and frozen foods, and the provision of fine-leaved vegetation or spawning mops. Fry care would follow standard small-tetra protocols — removal of eggs from adults, hatching in a separate container, and first foods of infusoria or rotifers before advancing to Artemia nauplii.
In the aquarium
Chrysobrycon myersi is rarely encountered in the ornamental fish trade and is essentially absent from mainstream hobby literature. It has not been the subject of aquarium husbandry guides comparable to those available for well-established tetra species, and any care notes must be inferred from its ecology and from the husbandry requirements of related glandulocaudin and stevardiine characids.
Based on its Andean foothill origins, the species would be expected to do best in soft to moderately soft, slightly acidic to neutral water in the tropical range typical of upper Amazonian tributaries, with temperatures broadly in the range appropriate for most small South American tetras. As a small schooling fish — maximum 2.5 in SL — it would suit a planted aquarium housing other similarly sized, non-aggressive South American community fish. The absence of hobby experience data for this species means that any prospective keeper would be working with limited published guidance.
Conservation
Chrysobrycon myersi is assessed as Least Concern on the IUCN Red List (published 2016, based on a 2014 assessment). The assessment notes that the species occurs in the Urubamba and Ucayali basins of the Peruvian Amazon, that its population is assumed stable, and that it is not known to occur within any protected area. The primary identified threat is illegal gold mining in the lower Pachitea River, which can damage riverine habitat through sedimentation, mercury contamination, and riparian disturbance.
The Least Concern listing reflects a lack of evidence for rapid population decline rather than confirmed population abundance or a wide, secure range — the species is restricted to a relatively limited section of the Peruvian Amazon, and available data are sparse. Continued monitoring of Andean foothill ichthyofauna in the Ucayali basin, particularly in the context of expanding extractive industries, remains relevant to reassessing its status in future IUCN evaluations.