Taxonomy & naming
Hyphessobrycon taguae was described by Carlos A. García-Alzate, César Román-Valencia, and Donald C. Taphorn in the journal Brenesia in 2010 (sometimes incorrectly cited as 2008). The description was part of a paper treating two new Hyphessobrycon species from the Putumayo River basin in Colombia, accompanied by keys to Colombian members of the genus. The type locality is a creek approximately 1 mi from Puerto Leguizamo on the road to La Tagua, Putumayo department, Colombia, at an elevation of 620 ft above sea level. The type specimen (IUQ 2288) was collected in 2008.
The species is placed in the large and taxonomically complex genus Hyphessobrycon, which belongs to the family Characidae. Within the genus, H. taguae is distinguished by a suite of meristic and morphological characters: 5–6 pored scales on the lateral line (notably few among Hyphessobrycon), conical maxillary teeth, five infraorbitals, 9 dorsal-fin soft rays, and 18–20 anal-fin soft rays. The valid name as recorded by Eschmeyer's Catalog of Fishes is Hyphessobrycon taguae García-Alzate, Román-Valencia & Taphorn, 2010. No subspecies or synonyms are currently recognised.
Morphology
Hyphessobrycon taguae is a small tetra reaching a maximum of 1 in standard length. The body plan is the typical compact, laterally compressed form of the genus. Meristically, the species is defined by 9 dorsal soft rays, 18–20 anal soft rays, and 33–34 vertebrae — a relatively high anal-fin ray count that contributes to the elongated ventral profile.
Colouration centres on a dark lateral band running along the flank, above which a contrasting red band provides a flash of colour. The combination of this red-over-dark pattern with low pored lateral-line scale counts (5–6) and conical maxillary teeth distinguishes H. taguae from its closest Colombian congeners. Males bear hooks on all fins, a character found in many Hyphessobrycon species and used in sexual determination; females presumably lack these hooks.
Habitat
The species inhabits small forest creeks and minor tributaries of the Río Putumayo in the Tagua–Puerto Leguizamo region of Putumayo department, Colombia. Collected specimens came from the Amaron and Tucunare creeks and comparable watercourses, where the substrate consists of organic detritus and decomposing leaf litter and vegetation — the leaf-litter creek habitat widespread in Amazonian lowland forests.
Water conditions at collection sites were markedly acidic and hypoxic: pH 6.0–6.2, conductivity 42–43 µS/cm, dissolved oxygen 0.42–0.75 mg/l (oxygen saturation 5.3–10%). These are among the most oxygen-poor freshwater conditions tolerated by any characid, suggesting physiological adaptation to blackwater or seasonally stagnant forest pools. The elevation of the type locality is 620 ft above sea level.
Feeding
FishBase records the diet of Hyphessobrycon taguae as insects and digested material. This is consistent with the feeding ecology of small Hyphessobrycon species generally, which are opportunistic micro-predators taking small invertebrates — insect larvae, microcrustaceans, and terrestrial insects fallen onto the water surface — supplemented by fine organic detritus.
Data on feeding biology specific to this species in either the wild or captivity remain sparse. In the aquarium, congeners of similar size and ecology are readily maintained on small live or frozen invertebrates (Daphnia, Artemia nauplii, micro-worms) and accept good-quality micro-pellets and fine flake.
Mating
No specific observations of mating behaviour in Hyphessobrycon taguae have been published. Based on the biology of the genus and the presence of fin hooks on males — a structure associated with clasping females during spawning rushes in many characids — the species is presumed to follow the typical Hyphessobrycon pattern of open, egg-scattering spawning.
In this general model, males display to and pursue females, with courtship culminating in rapid side-by-side dashes during which eggs and sperm are released simultaneously. Spawning activity in congeners is often triggered by morning light and is most intense in fine-leaved vegetation or over substrate that provides adhesion sites for the deposited eggs. No parental care is expected.
Breeding
No captive breeding records for Hyphessobrycon taguae appear in the literature or hobby sources. By analogy with other small Hyphessobrycon species, the breeding mode is expected to be egg-scattering over fine-leaved plants or spawning substrate, with small adhesive eggs and no parental care. Adults of such species will consume their own eggs and fry if not separated after spawning.
The extreme natural water conditions — very low pH and near-hypoxic dissolved oxygen — suggest the species may require unusually soft, acidic water to spawn successfully in captivity, a challenge that likely contributes to its absence from the trade. Fry of small Hyphessobrycon species are typically tiny at hatching and require infusoria or commercial liquid fry foods as first foods before accepting Artemia nauplii.
In the aquarium
Hyphessobrycon taguae is essentially absent from the aquarium hobby and is not commercially available. Its natural habitat in extreme blackwater conditions — pH around 6.0, conductivity under 45 µS/cm, dissolved oxygen below 1 mg/l — would demand careful replication for long-term maintenance, making it a specialist subject rather than a community fish.
For any keeper who obtained specimens, a biotope-style setup approximating the Putumayo forest creek would be most appropriate: soft, very acidic, low-conductivity water, heavy leaf litter, minimal water movement, subdued lighting, and no high-oxygen demand tankmates. Small, peaceful species from the same drainage — other micro-tetras, small pencilfish, or dwarf cichlids adapted to blackwater — would be logical companions. As with most Hyphessobrycon, a group of at least six individuals would reduce individual stress and encourage natural behaviour.
Conservation
Hyphessobrycon taguae is assessed as Least Concern (LC) on the IUCN Red List, assessed in October 2014. The listing reflects the absence of evidence of major range-wide population declines rather than detailed population data; field survey information for this micro-endemic is limited. The species is known from a restricted area of the Putumayo drainage in southern Colombia, a region that has experienced ongoing deforestation, agricultural expansion, and associated sedimentation and water-quality changes in its forest waterways.
The species is included in the checklist of freshwater fishes of Colombia, and its discovery underscores the continued ichthyological richness of the Putumayo basin. Given its dependence on intact, low-conductivity forest creeks and the ongoing pressure on Amazonian forest habitats, continued monitoring of the Putumayo ichthyofauna is warranted.