Taxonomy & naming
Andromakhe tupi was formally described in 2003 by María de las Mercedes Azpelicueta, Juan Marcos Mirande, Adriana Edith Almirón and Jorge Casciotta from material collected in the upper Paraná River basin. The holotype is a male measuring 2.76 in standard length. Eschmeyer's Catalog of Fishes (CAS) records the original combination as Andromakhe tupi, and the authority is cited with four co-authors.
In 2020, Terán and colleagues published a large phylogenetic revision of the sprawling Astyanax complex under the title "Opening the Trojan Horse", which erected several new genera and resurrected others. Within that work, the species was transferred to the newly erected genus Andromakhe, making the current valid name Andromakhe tupi (Azpelicueta, Mirande, Almirón & Casciotta, 2003); parenthetical authority applies because the species moved out of its original genus. Andromakhe is characterised within related Astyanax-lineage taxa by an unusually high number of maxillary teeth. The species has no widely used common name in the hobby.
This fish was long listed as Hyphessobrycon tupi; Eschmeyer's Catalog of Fishes places the species in Andromakhe, and the current combination Andromakhe tupi is followed here.
Morphology
As with most small Hyphessobrycon and Andromakhe species, A. tupi is a compactly built, laterally compressed characin. The holotype male reached 2.76 in standard length, placing it toward the larger end of the Hyphessobrycon size range while remaining modest by characin standards. Specific colouration and meristic details are not extensively documented in the accessible literature for this species; detailed morphological descriptions are contained in the original 2003 description.
The genus Andromakhe is distinguished from allied genera partly by dentition — an elevated maxillary tooth count compared with related lineages in the Astyanax group. Beyond this diagnostic character, the gross body plan is that of a generalist Paraná-basin tetra: a moderately deep, silvery body with the standard lateral band and dark caudal peduncle spot characteristic of many characins in this clade. Data remain sparse in the public literature; hobbyists working with the species should consult the original description for full meristic counts.
Habitat
Andromakhe tupi is endemic to the upper Paraná River basin, with a distribution spanning Argentina, Brazil, and Paraguay. The middle Paraná basin is recognised as a biogeographically important region with high levels of fish endemism, and A. tupi is among the specialist species restricted to it.
The broader Paraná system encompasses a variety of freshwater habitats: clear and turbid channels, floodplain lagoons, marginal pools, and smaller tributary streams. Smaller tetra species in this system typically occupy vegetated shallows and edge habitats, where structure and cover provide refuge from predators. Precise habitat data for A. tupi at type-locality level are not fully reported in the open literature; water-chemistry parameters typical for the upper Paraná are warm subtropical to tropical temperatures, circumneutral to slightly acidic pH, and soft to moderately hard water, though site-specific data for this species' collecting locality have not been captured in available sources.
Feeding
Detailed dietary studies specific to Andromakhe tupi are not available in the accessible literature. Small Hyphessobrycon and related Andromakhe species are generally regarded as opportunistic omnivores, taking small invertebrates — aquatic insect larvae, microcrustaceans — along with algal material and fine organic detritus, depending on what each microhabitat offers.
In an aquarium setting, fish of this group typically accept a wide range of small prepared and live foods. Finely crushed flake, micro-pellets, and small live or frozen invertebrates such as Daphnia, brine shrimp nauplii, and micro-worms suit the mouth size and feeding behaviour expected for a compact Paraná tetra. A varied diet supports good condition and colouration.
Mating
No published spawning observations specific to Andromakhe tupi are recorded in the sources available, but the species belongs to a clade of egg-scattering characins that follow a well-documented reproductive pattern. In related Hyphessobrycon and Andromakhe species, males compete for access to receptive females through lateral displays, spreading fins and presenting body colouration.
Spawning typically takes place among fine-leaved aquatic vegetation or submerged roots, where adhesive eggs are deposited among plant filaments. No parental care is provided; both sexes ignore or consume eggs after spawning. The general pattern for small Paraná tetras involves short, intense spawning bouts followed by a refractory period before the next cycle.
Breeding
Specific captive breeding accounts for Andromakhe tupi are not documented in the accessible literature, and the species appears rarely if ever in hobby trade. Based on the biology of closely related small Hyphessobrycon and Andromakhe species, the expected captive approach would follow standard tetra protocol: a conditioned pair or small group moved to a dedicated breeding tank with bunches of fine-leaved plants or spawning mops, slightly soft and acidic water, and subdued lighting.
Eggs would be expected to be small, adhesive, and semi-transparent, deposited among plant material. Hatch times for small tetras at tropical temperatures typically run 24–48 hours, with free-swimming fry emerging after a further 24–72 hours of yolk-sac absorption. Adults should be removed to prevent egg predation. First foods for the fry would consist of infusoria-grade microorganisms or commercial liquid fry food, progressing to newly hatched brine shrimp nauplii as the fish grow. Data sparse; experienced breeders of small South American tetras are the best resource.
In the aquarium
Andromakhe tupi is essentially absent from the ornamental fish trade and is not a species the typical aquarist will encounter. It is a scientific and biogeographic subject of interest rather than a hobby fish in the conventional sense. Should specimens ever become available, the care framework would logically follow that of other small Paraná-basin tetras: a peaceful community aquarium with other small, non-aggressive species, adequate planting for cover and security, and water parameters aligned with subtropical South American conditions.
A group of six or more individuals would be preferable for behavioural expression, as shoaling provides security and elicits natural activity patterns. Given the species' endemic status and restricted natural range, any captive specimens would be of considerable scientific and conservation interest, and documentation of their care and breeding would add meaningfully to the thin existing literature.
Conservation
Andromakhe tupi has not been formally assessed by the IUCN Red List and carries a status of Not Evaluated (NE) as of 2026. This reflects the species' obscurity rather than any confirmed abundance: small, narrowly distributed endemics from the Paraná basin have often been overlooked in conservation assessments relative to more commercially prominent or widespread species.
The middle Paraná basin faces significant anthropogenic pressure, including agricultural runoff, deforestation of riparian zones, flow regulation from large hydroelectric dams, and invasive species introductions. For a species with a restricted distribution confirmed across Argentina, Brazil, and Paraguay, these pressures are non-trivial threats. A formal IUCN assessment using current occurrence data and threats analysis would help establish baseline status and identify conservation priorities. Until such data exist, its standing remains uncertain.