Taxonomy & naming
Sternarchella curvioperculata was described by Godoy in 1968 from the upper Paraná River basin and placed in the genus Sternarchella, within the family Apteronotidae — the ghost knifefishes — inside the order Gymnotiformes, the New-World electric knifefishes. Gymnotiformes are bony fish but an unusual lineage, defined by an electric organ and a single long anal fin used for propulsion in place of a normal tail; the Apteronotidae are distinguished within the order by an electric organ built from modified nerve tissue rather than muscle, giving them a fast, continuous wave-type discharge used for electrolocation and communication.
The genus placement of this species is disputed. A taxonomic revision of Sternarchella (published in Neotropical Ichthyology) excludes S. curvioperculata from the genus on morphological grounds: it carries 13–14 small scales above the lateral line, where true Sternarchella species have only 5–9, a difference the reviewing authors judge sufficient to place it outside the genus, likely closer to Apteronotus in the strict sense. That reassessment was made from the original description rather than a re-examined physical specimen, so the species' correct genus is not yet settled in the literature the Catalog of Fishes treats as authoritative for valid names. The species epithet curvioperculata comes from Latin curvus ("curved") and operculatus ("furnished with a lid"), referring to the concave dorsal margin of the opercle, the bony gill cover — the feature that seems to have anchored the original description.
As with all Gymnotiformes, this fish is entirely unrelated to the Asian featherback and clown knifefishes (Chitala, Notopterus) despite sharing the common name "knifefish" — the resemblance is convergent body shape, not kinship.
Morphology
Detailed morphological data specific to Sternarchella curvioperculata — total length, exact body proportions, coloration — is data sparse; the species is known mainly from its original description and the scale counts used to argue its genus placement. What can be said follows from its family: like other Apteronotidae it is a laterally compressed, blade-bodied fish with no dorsal fin and no true tail fin, moving by rippling waves along a single elongated anal fin that runs most of the length of the underside. This lets it swim backward as readily as forward, useful for backing out of tight cover.
The diagnostic feature on record is the scale count: 13–14 small scales above the lateral line, distinctly more than the 5–9 typical of true Sternarchella, and the curved dorsal margin of the opercle referenced in its name. Like the rest of the order it is scaleless in the ordinary sense along most of the body — the electric organ runs down the flank beneath the skin, and the skin itself carries the sensory pores that read the field it generates.
Habitat
Sternarchella curvioperculata was described from the upper Paraná River basin in South America, placing it within the wider Paraná–Paraguay drainage of Brazil and neighboring countries. Specific habitat data — depth, current, substrate, water chemistry at the type locality — is not available in the sources reviewed here, and should be treated as data sparse for this species specifically.
More broadly, Apteronotidae as a family are creatures of warm, often turbid or tannin-stained Neotropical river water, typically found in deeper channels and among submerged roots and cover, active mainly at night. Where eyesight is of little use in dark or sediment-laden water, the electric sense takes over as the primary way these fish navigate and detect prey or rivals.
Feeding
No diet-specific data for Sternarchella curvioperculata was found in the sources reviewed; this remains data sparse. Ghost knifefishes as a family are nocturnal carnivores that hunt largely by electrolocation, detecting the electrical signatures of small invertebrates hidden in sediment, leaf litter or root tangles rather than relying on sight.
Given the family pattern, S. curvioperculata most plausibly feeds on small aquatic invertebrates — insect larvae, worms and similar benthic prey — located at night through its electric sense, but this should be read as an inference from its relatives rather than a confirmed observation for this species.
Mating
No courtship or mating behavior specific to Sternarchella curvioperculata has been documented in the sources reviewed. What is well established for the family is the role electricity plays in Apteronotidae courtship generally: the wave-type electric organ discharge carries information about a fish's identity, sex and reproductive state, and in the best-studied relative, the brown ghost knifefish Apteronotus leptorhynchus, males and females shift their discharge frequency toward one another during courtship in what researchers describe as an electric duet. Discharge frequency in this family is also temperature-dependent, and electrocommunication appears to intensify at night alongside the fish's general activity pattern.
Whether S. curvioperculata shows the same electric courtship signalling has not been studied directly, but given how conserved the trait is across Apteronotidae, it is a reasonable expectation rather than a confirmed fact for this exact species.
Breeding
Breeding biology for Sternarchella curvioperculata is undocumented — this species has essentially no aquarium history and no published husbandry or spawning record. Like other Apteronotidae it is presumed to be an egg-layer, based on the reproductive mode documented across the family, but nothing specific to its own spawning site, egg number, incubation, or parental behavior has been recorded.
What is known of the family more broadly is that ghost knifefishes are rarely bred even in captivity — most trade specimens of the popular species are wild-caught or hormone-induced on commercial farms — and that no substantial parental care has been documented in the group. Given the complete absence of species-specific breeding data, this is best treated as poorly documented rather than described one way or another.
In the aquarium
Sternarchella curvioperculata is not an aquarium fish in any meaningful sense — it has no established trade history, and the sources reviewed here provide no husbandry record for it. It should not be sought out or kept on the assumption that it behaves like its better-known relatives.
What can be said comes from the family: Apteronotidae are scaleless and correspondingly sensitive to ammonia and nitrate, and to copper-based or harsh medications, which typically need reduced dosing. They are nocturnal electroreceptive predators that want dim lighting, secure cover such as tubes or root tangles, and are generally unsafe with small or bite-size tankmates after dark. Any of these general points would need to be treated as inference rather than confirmed guidance for this particular, essentially unkept species.
Conservation
Sternarchella curvioperculata does not appear to have been formally assessed on the IUCN Red List; no accessible IUCN page for the species was found, and its status is treated here as Data Deficient by default. This is common among narrow-range or poorly collected Gymnotiformes described from a single basin decades ago and rarely revisited since.
The upper Paraná basin, its type locality, is a heavily developed river system subject to damming, agricultural runoff and habitat modification across its range, pressures that in principle could affect a narrow-range species — but without further survey work or a formal assessment, the conservation status of S. curvioperculata specifically cannot be stated with confidence. It is best treated as a species in need of taxonomic and conservation attention rather than one with a known, quantified outlook.