Taxonomy & naming
Bryconamericus pectinatus was described by Richard P. Vari and Dean J. Siebert in 1990. The type locality is in Parque Nacional del Manú, Departamento Madre de Dios, Peru, in the upper Madre de Dios drainage of the western Amazon basin. The specific epithet pectinatus refers to a comb-like or pectinate structure, most likely an allusion to the pectoral fin stripe pattern that is characteristic of the species and helps distinguish it within the genus.
Bryconamericus is a large and historically difficult genus of small characins in the family Characidae, and its limits have shifted repeatedly as systematic revisions have worked through the many superficially similar small tetra lineages of South America. The Catalog of Fishes (Eschmeyer, CAS) records Bryconamericus pectinatus Vari & Siebert, 1990 as the valid name. FishBase records the species only from Peru.
Morphology
Bryconamericus pectinatus is a slender, fusiform small tetra, reaching approximately 1–1.5 in in standard length. Like other members of the genus it has a moderately compressed body, a small terminal mouth, and the single adipose fin typical of characins. The body is silvery, with the lateral line region often carrying a subtle darker midlateral stripe. The species is distinguished within Bryconamericus by a pectinate, comb-like stripe pattern associated with the pectoral fin — the feature encoded in the specific epithet.
Sexual dimorphism is subtle, as is common in small Bryconamericus. Females are typically deeper-bodied when gravid. Beyond that, reliable external separation of the sexes requires close examination. The species lacks the dramatic colour of many hobbyist tetras; its appeal lies in the quietly elegant form common to the group, and in the natural behaviour of a wild-caught shoal.
Habitat
The type locality of Bryconamericus pectinatus lies within Parque Nacional del Manú, in the Madre de Dios drainage of southeastern Peru. The Manú drains the eastern Andean piedmont into the lowland Madre de Dios, spanning swift foothill channels and meandering lowland reaches.
Bryconamericus species in this region typically inhabit small to medium streams with clear to lightly tannin-stained water, moderate current, and substrates of sand, gravel, and leaf litter. Water conditions in Andean foothill streams are generally soft to moderately hard and acidic to neutral. Available hobbyist and ecological notes suggest acidic to neutral, blackwater or clearwater stream conditions with temperatures in the range of 72–79 °F. Data on the precise microhabitat preferences of B. pectinatus specifically are sparse.
Feeding
Bryconamericus pectinatus is an omnivore, as is typical for small, stream-dwelling characins of its guild. In nature, small Bryconamericus feed opportunistically on small invertebrates — aquatic insect larvae, microcrustaceans, and terrestrial insects that fall to the surface — supplemented by algae, detritus, and organic particles. The species likely forages in the middle and upper water column and among substrate debris.
In the aquarium, captive individuals of similar small characins accept a wide range of prepared foods including fine flake, micro-pellets, and crushed freeze-dried foods, alongside live or frozen offerings such as Daphnia, Moina, baby brine shrimp, and micro-worms. A varied diet supports condition and encourages the natural foraging behaviour of the shoal.
Mating
Specific courtship observations for Bryconamericus pectinatus are not documented in the available literature. Based on the biology of the genus and family, the species is assumed to be an egg-scattering open spawner typical of small characins: males pursue females and spawning occurs in open water or among fine-leaved vegetation, with no pair bond formation and no parental care.
In related small Bryconamericus and comparable Characidae, males often develop small hooks on the anal fin rays — a feature associated with spawning behaviour in some characin lineages — and may show mild secondary colouration or increased activity during courtship. Whether B. pectinatus exhibits anal fin hooks or other secondary sexual characters has not been confirmed in the available sources.
Breeding
No captive breeding records for Bryconamericus pectinatus appear in the hobbyist or scientific literature available to date. By analogy with other small, stream-dwelling characins in the genus, the reproductive mode is likely egg-scattering with adhesive or semi-adhesive eggs deposited among fine-leaved aquatic plants or over open substrate. Parental care is not expected; adults should be considered likely to consume eggs.
Should captive breeding be attempted, the standard approach for small stream tetras applies: condition a group of adults on varied live and frozen foods, provide a heavily planted tank or spawning mops, and remove adults after spawning. Eggs in small characins of this type typically hatch within 24–48 hours at appropriate temperatures, and the fry require very fine first foods such as infusoria or commercial liquid fry food before accepting newly hatched brine shrimp.
In the aquarium
Bryconamericus pectinatus is essentially unknown in the ornamental fish trade and is unlikely to be encountered outside specialist collections or importations of Peruvian stream fish. It is a small, undemanding tetra by all indications — suitable for a calm, well-planted stream-biotope setup with soft, slightly acidic water and gentle flow, kept as a shoal of six or more individuals.
Given its natural habitat in Andean foothill streams, conditions in the range of 72–79 °F, pH 6.0–7.5, and soft to moderately hard water are appropriate starting points. It is peaceful and would mix well with other small, non-aggressive species from the same zoogeographic zone. Because so little captive data exists, keepers who acquire this species are in a position to document genuinely new observations about its behaviour and care.
Conservation
Bryconamericus pectinatus has not been assessed on the IUCN Red List and carries a status of Not Evaluated (NE). This is common for obscure, small-bodied characins whose range and population trends are poorly documented — taxonomically similar species are numerous and field surveys rarely focus on them at a species-specific level.
Andean-piedmont drainages of the region face ongoing pressures from habitat degradation, agriculture, extractive infrastructure, and water quality changes in the broader catchment. Whether these pressures affect B. pectinatus populations specifically is unknown. The absence of an IUCN assessment should not be read as evidence of security; it reflects a data gap rather than confirmed stability. The species is not known to be in trade, which limits both exploitation pressure and the hobbyist community's ability to contribute captive-breeding conservation records.