Taxonomy & naming
Sternopygus embera was described in 2026 by Torgersen, Galindo-Cuervo, Ortega-Lara, Lujan, Reis and Albert as part of a study deconstructing the long-recognized Sternopygus macrurus species complex — a widespread "species" that genetic and morphological work has been splitting into several distinct, more narrowly distributed ones. It belongs to the family Sternopygidae, the glass and rattail knifefishes, within the order Gymnotiformes, the New-World electric knifefishes. Gymnotiformes are bony fish but an unusual lineage: they lack a dorsal fin and a conventional tail, swim on a single long anal fin, and navigate and hunt using a weak electric organ discharge (EOD) that builds a field around the body, a sense called electrolocation. Sternopygus produces a continuous, steady-frequency "wave-type" discharge, the hallmark of its family, in contrast to the pulsed discharges of groups like Gymnotus.
Despite outward resemblance to S. macrurus, S. embera is phylogenetically nested within a different lineage, the S. aequilabiatus species group, and is diagnosed by a distinctive Weberian apparatus (the chain of bones linking swim bladder to inner ear), the complete absence of a humeral spot and of pigment bars or saddles, endopterygoid teeth, a vertically oriented ascending process of the endopterygoid bone, a short snout, a convexly curved neurocranium margin, and 22–23 precaudal vertebrae. The species name honours the Emberá people, indigenous to the Chocó region of Colombia where the fish was collected. The Catalog of Fishes is the authority for the valid name.
Morphology
Like other rattail knifefishes, Sternopygus embera has an elongated, laterally compressed body that tapers gradually to a fine, whip-like tail, with no dorsal fin and no distinct caudal fin — propulsion comes almost entirely from the long anal fin running beneath most of the body's length. The published description records a maximum length of 19 in total length, making it one of the larger gymnotiforms in its range, though most individuals examined were smaller. No colour pattern is described beyond the diagnostic absence of a humeral spot and of dark bars or saddles that mark related species, a plain appearance that is itself one of the identifying features separating it from S. macrurus.
As in all Sternopygidae, an electric organ runs along the body and the skin carries the electroreceptor pores that read the field it produces — the sensory system these fish rely on more than sight in the dim, often turbid water they inhabit. The description found no external sexual dimorphism in the material examined, though gonad tissue was sampled to confirm sex; as in related Sternopygus, males and females are likely distinguished chiefly by internal anatomy and by differences in electric discharge frequency rather than by outward appearance.
Habitat
Sternopygus embera is, on current knowledge, a narrow-range endemic of the trans-Andean Pacific slope of Colombia, known only from the Río Baudó and Río San Juan drainages in the Chocó and Valle del Cauca departments. This is unusual for the genus Sternopygus, most of whose species range across large stretches of Amazonian or Orinocan drainage; S. embera instead occupies a comparatively small, biodiverse pocket of rainforest river system on the Pacific side of the Andes, separate from the Amazon basin. The type locality lies on the Río Baudó at roughly 5°12′N, 76°57′W, and specimens have been recorded from sea level up to about 3215 ft elevation.
Within that range the species has been found in both clear and turbid shallow water less than 7 ft deep, over stone, sand and woody debris in the deltas and main channels of its home rivers and their tributaries. Collections show a seasonal pattern of abundance, with fish most commonly encountered from May to September and peaking in June–July, coinciding with the region's dry season. No pH or temperature readings were recorded from the type material, but the habitat sits squarely within the warm, humid Chocó rainforest belt typical of Pacific-slope Neotropical rivers.
Feeding
Dedicated feeding studies of Sternopygus embera have not been published, but its family's habits are well established and almost certainly apply here. Rattail knifefishes are nocturnal micro-predators, foraging after dark over sand, stone and woody debris for small invertebrates — aquatic insect larvae, worms and small crustaceans — locating prey largely by electrolocation rather than sight, sensing the way a living creature distorts the fish's own electric field even when it is hidden in sediment or debris.
In the aquarium, congeners such as S. macrurus take a similar range of meaty foods — bloodworm, blackworm, chopped earthworm and other frozen or live invertebrate foods — usually offered after dark when the fish becomes active. No aquarium feeding data specific to S. embera exists; this description is extrapolated from the genus and should be treated as a starting point rather than an established protocol for this particular species.
Mating
Nothing about courtship has been documented for Sternopygus embera specifically — the description paper is a taxonomic account, not a behavioural one. What is known comes from its well-studied relative S. macrurus, which produces a continuous wave-type electric organ discharge whose frequency is sexually dimorphic: males typically discharge at a lower frequency than females, a difference modulated by circulating androgens around the breeding season. In S. macrurus, males defend a territory and intensify and interrupt their discharge pattern as part of courtship, signalling to and assessing potential mates through the electric channel rather than through visual display.
Given that S. embera sits within the broader Sternopygus radiation and shares the same wave-type electrogenic system, a broadly similar electric courtship — territorial males, dimorphic discharge frequencies, and signalling via discharge modulation — is a reasonable expectation, but it has not been confirmed for this species and should be treated as inference from the genus rather than observed fact.
Breeding
There is no published breeding record for Sternopygus embera, in the wild or in captivity; it is a fish known so far only from a small series of collected specimens used to describe the species. By analogy with S. macrurus, which spawns adhesive eggs — a single female recorded carrying roughly 6,500 of them — scattered among fine cover during the rainy or pre-rainy season, S. embera likely follows a similar pattern of seasonal, cover-dependent egg-laying with no meaningful parental care once eggs are released; in S. macrurus, hatching occurs around four days after spawning and larvae begin feeding around day eleven, with the electric organ and electroreceptors already functional at first feeding.
Given the species was only described in 2026 and is not established in the aquarium trade, none of this can be taken as more than an informed extrapolation. Breeding in captivity has not been attempted or reported, and the honest position is that this remains entirely undocumented for the species itself.
In the aquarium
Sternopygus embera is not currently established in the aquarium hobby — it is a 2026 taxonomic split from the S. macrurus complex, known from a handful of scientific collections, and any care guidance has to be drawn from its close relatives rather than from hobbyist experience with this exact species. Like other rattail knifefishes it should be assumed to need a large, mature aquarium given an adult length approaching half a metre, warm water, and dim lighting with generous cover — root tangles, pipes or dense planting — to shelter in by day, since it is a nocturnal fish that reads its surroundings electrically rather than visually.
As in all gymnotiforms, the species is scaleless, which makes it unusually sensitive to ammonia and nitrate and to medications containing copper or formalin; any treatment should be dosed with caution and only after ruling out gentler options. Tankmates should be too large to be eaten and not prone to nipping the fish's long fin. Given how recently it was described and its apparently narrow natural range, keeping wild-collected S. embera should be approached conservatively, and prospective keepers should not expect captive-bred stock to be available.
Conservation
Sternopygus embera has not yet been evaluated by the IUCN Red List — it was only formally described in 2026 and currently carries no conservation assessment (Not Evaluated). Its known range is confined to the Río Baudó and Río San Juan drainages on Colombia's Pacific slope, a comparatively restricted area for a Sternopygus species, which makes it a candidate narrow-range endemic of the kind that can be vulnerable to local pressures even without formal assessment.
The Chocó region is one of the wettest and most biodiverse parts of the Neotropics, but it faces mounting pressure from logging, small-scale and industrial mining, and associated water pollution, all of which could affect river habitat in the Baudó and San Juan systems. No population trend or specific threat data exists yet for this species; an IUCN assessment, when it comes, would be the first real basis for judging its conservation status.