Taxonomy & naming
Sternarchella patriciae was described by Evans, Crampton & Albert in 2017 as part of a taxonomic revision of the genus Sternarchella, published in the Brazilian journal Neotropical Ichthyology. It belongs to the family Apteronotidae, the ghost knifefishes, within the order Gymnotiformes — the New-World electric knifefishes. Gymnotiformes are bony fish, but unusual ones: they are defined by an electric organ used for electrolocation and communication, and by a long ribbon-like anal fin that provides essentially all of their propulsion, since they have no proper dorsal or caudal fin. Within the order, the Apteronotidae are distinguished by an electric organ built from modified nerve cells rather than muscle tissue, giving them the fastest, most refined wave-type discharges of any knifefish group.
The genus Sternarchella — sometimes called the bulldog knifefishes for their blunt heads — currently comprises around a dozen species distributed across Amazonian and Orinoco drainages, most of them poorly known deep-channel fish. S. patriciae is separated from its congeners by fine anatomical detail: an eye diameter of roughly 7-9% of head length and a distinctive bony ridge — described as a "crown of thorns" — at the parietal-supraoccipital border of the skull. As with all Gymnotiformes, it should not be confused with the unrelated Asian featherback and clown knifefishes (Chitala, Notopterus), which share only a superficially similar body shape by convergent evolution, not ancestry. The Catalog of Fishes is the authority for the valid name.
Morphology
Sternarchella patriciae reaches a maximum recorded length of about 8 in total length, based on the largest specimen examined in its description; the holotype itself measured around 7 in. Like other members of its genus it has the blunt, deep-headed profile that gives the bulldog knifefishes their nickname, a laterally compressed blade-shaped body, and no dorsal fin — propulsion comes from the long undulating anal fin running beneath the body, which lets it move forwards and backwards with equal ease. A thin electric organ runs the length of the body, and the skin over it is dense with electroreceptive pores that read the field the organ produces.
As in all Apteronotidae, the discharge is wave-type: a continuous, near-sinusoidal electric signal produced at a steady frequency, in contrast to the intermittent pulses of families such as Gymnotidae. This gives ghost knifefishes an unusually refined, always-on electric sense well suited to threading narrow gaps and detecting prey in total darkness. The species is scaleless, like all gymnotiforms, which leaves the skin exposed and sensitive. Details of external sexual differences are not documented in the source description.
Habitat
Sternarchella patriciae is known only from the Madre de Dios basin, part of the upper Madeira River system in the Peruvian Amazon. The type locality is the Río Madre de Dios roughly 1 mi upstream of the bridge at Puerto Maldonado, and the species has been collected in the main channel at depths of 2 to 50 metres — squarely a deep-water river fish rather than an inhabitant of shallow margins or floodplain lagoons.
Water in the Madre de Dios basin is warm and tropical, with recorded temperatures around 76–80 °F, pH ranging from acidic to near-neutral (about 5.1-7.9), and healthy dissolved oxygen levels near 7 mg/L. These are typical soft, tannin-influenced Amazonian conditions, and as with other ghost knifefishes the dim, current-swept deep channel is exactly the setting in which an always-on electric sense outperforms vision. Nothing in the available literature suggests this species uses any other habitat type; its known range appears to be a single river system.
Feeding
Gut-content analysis in the species description found Sternarchella patriciae feeding primarily on larger aquatic insect larvae — dragonfly and damselfly nymphs (Odonata) and mayfly nymphs (Ephemeroptera) — along with juvenile fishes. This marks it as a more substantial predator than many smaller electric knifefishes, taking prey items large enough to require active pursuit rather than simply grazing fine invertebrates from the substrate.
As in other Apteronotidae, prey detection in the deep, dark river channel is presumed to rely heavily on electrolocation: the wave-type discharge lets the fish sense the electrical signature of buried or hidden prey where eyesight would be of little use. No specific account of hunting behaviour — nocturnal activity pattern, foraging strategy — has been published for this species beyond the stomach-content data, so further detail here would be guesswork.
Mating
No courtship or spawning behaviour has been documented for Sternarchella patriciae; the species is known from museum specimens collected for taxonomic study, not from field or aquarium observation of live behaviour. What can be said follows from its family: in Apteronotidae generally, the wave-type electric organ discharge doubles as a social signal, carrying information about a fish's species, sex and possibly readiness to spawn, and courtship in well-studied relatives such as the brown ghost knifefish (Apteronotus leptorhynchus) involves both fish shifting discharge frequency in a kind of electrical duet as they approach one another in the dark.
Whether S. patriciae shows comparable behaviour is not established. Given how little is known even of its basic ecology, any specific claim about pairing, courtship displays or spawning sites in this species would be invented rather than sourced, so none is offered here.
Breeding
Breeding biology in Sternarchella patriciae is entirely undocumented. There is no published record of its reproductive mode, spawning season, egg deposition, or any parental care, and — as an obscure deep-channel species never recorded in the aquarium trade — none is likely to appear soon. Based on general knowledge of the family, Apteronotidae are egg-layers that scatter eggs among cover such as roots and crevices, without an extended pair bond or substantial guardianship of the brood, but this is inference from relatives rather than direct observation of this species.
For the record, this is a fish that has essentially never been bred in captivity, wild or otherwise — data here is sparse to the point of nonexistence, and that gap is itself the honest headline for the species.
In the aquarium
Sternarchella patriciae is not a species found in the aquarium trade. It is known only from scientific collecting in deep river channels of the Madre de Dios basin, and there is no record of live specimens being kept, imported, or bred by hobbyists. Anything written about its husbandry would therefore be speculation extrapolated from better-known ghost knifefishes rather than documented fact for this species.
What can be said with confidence, by extension from its family and its deep, soft, acidic-to-neutral, warm home water, is that any care attempt would need to follow the same principles that apply to all Apteronotidae: a large, dimly lit tank with strong but gentle water movement, ample cover, scrupulous water quality, and great caution with medications, since gymnotiforms are scaleless and unusually sensitive to copper-based treatments and to ammonia and nitrate. This is offered as a general caution, not a validated protocol — nobody has kept this species in a home aquarium to confirm it.
Conservation
Sternarchella patriciae has not been formally assessed by the IUCN Red List; no specific conservation status has been published for the species, which is consistent with its status as a recently described (2017), narrow-range Amazonian endemic known from only a small number of specimens. It is best treated as Data Deficient in practical terms, pending a formal evaluation.
As a single-basin endemic restricted to the Madre de Dios drainage, the species shares the general vulnerabilities of range-restricted Amazonian river fish: habitat disturbance from deforestation, small-scale and artisanal gold mining (a documented pressure in the Madre de Dios region, associated with mercury contamination and sediment loading), and broader upper-Madeira hydrological change from dam construction elsewhere in the basin. None of these pressures has been specifically linked to S. patriciae in the literature, so this is offered as basin-level context rather than a species-specific threat assessment.