Taxonomy & naming
Eigenmannia meeki was described in 2017 by Dutra, de Santana and Wosiacki in the journal Copeia, based on specimens collected from the Río Pucuro, part of the Río Tuíra basin in southeastern Panama. It belongs to the family Sternopygidae — the glass and rattail knifefishes — within the order Gymnotiformes, the New-World electric knifefishes, a group of bony fish defined by their electric organs and their ribbon-like anal fin rather than by any resemblance to typical aquarium fish. The genus Eigenmannia is the most species-rich in the order, with more than thirty described species, and E. meeki was notable at description as the first member of the genus recorded from a Central American drainage and the fifth gymnotiform species known from the Río Tuíra basin.
Despite sharing the common name "knifefish" with the Asian featherback and clown knifefishes (Chitala, Notopterus), the two groups are not related; the blade-like body shape is a case of convergent evolution, not shared ancestry. The species epithet honors Seth Eugene Meek (1859–1914), the American ichthyologist whose surveys documented much of Panama's fish diversity. The Catalog of Fishes is the authority for the valid name.
Morphology
Eigenmannia meeki has the elongated, laterally compressed body typical of the genus, tapering to a fine point at the tail with no dorsal fin and no distinct caudal fin. The type series shows a densely pigmented body carrying dark chromatophores over most of its surface, broken by a pale stripe running above the base of the anal fin. The mouth is subterminal, and the body is covered in cycloid scales rather than being fully naked, distinguishing it in fine anatomical detail from some congeners.
Meristic counts from the original description place it within the normal range for the genus: roughly 140–168 lateral-line scales running to the end of the anal fin, 211–240 anal-fin rays, 20–23 dentary teeth arranged in two rows, 10–15 scale rows above the lateral line, and 14–15 preanal vertebrae. The holotype measured 9.5 in to the end of the anal fin, with a paratype at 6.5 in — sizes consistent with a mid-sized Eigenmannia. As in other Sternopygidae, propulsion comes almost entirely from undulations of the long anal fin, and the species carries a weak electric organ generating a continuous, wave-type discharge used for electrolocation and, most likely, communication between individuals.
Habitat
Eigenmannia meeki is known only from the Río Pucuro, a tributary within the Río Tuíra basin of southeastern Panama near the Colombian border — a trans-isthmian, Neotropical drainage rather than an Amazonian one. Its description as the northernmost species in its genus underscores how narrow this range appears to be: no other populations have been reported elsewhere.
Sternopygids in general favor slow-flowing streams, river margins, deep channels and floodplain habitat around submerged roots, leaf litter and floating vegetation — structurally complex, dimly lit water where an electric sense is more useful than eyesight. There is no specific habitat description published beyond the type locality data, so finer details of the Río Pucuro population's preferred microhabitat remain data sparse.
Feeding
No dedicated dietary study of Eigenmannia meeki has been published. Based on the well-studied biology of its genus and family, it is almost certainly a nocturnal micro-predator, foraging after dark for small invertebrates — aquatic insect larvae, worms and tiny crustaceans — hidden in sediment, leaf litter or root tangles, located by electrolocation rather than sight.
This pattern holds broadly across Eigenmannia and the wider Sternopygidae: peaceful toward fish too large to be prey, but persistent, methodical hunters of anything smaller. Specific feeding records for this species are lacking, and this should be read as an inference from its relatives rather than as confirmed fact for E. meeki.
Mating
Nothing has been published on courtship behavior in Eigenmannia meeki itself. In the wave-type Sternopygidae generally, and in the well-studied glass knifefish Eigenmannia virescens in particular, the continuous electric organ discharge doubles as a social signal — frequencies differ between males and females, and the genus is the classic experimental animal behind the jamming-avoidance response, in which two fish shift their discharge frequencies apart to avoid interference when their fields overlap. It is reasonable to expect that courtship in E. meeki follows the same general pattern of electrical signalling paired with physical approach, but this has not been documented for the species and should be treated as inference from its relatives, not observed fact.
Breeding
There is no published breeding record for Eigenmannia meeki; it is not known to have been kept or spawned in captivity. Sternopygids as a group are egg-layers that scatter adhesive eggs among plant roots or floating vegetation, typically triggered by warm, soft, rising-water conditions associated with the wet season, and they generally show little or no parental care once eggs are laid. Eigenmannia virescens, the most familiar glass knifefish in the hobby, breeds more readily in captivity than most gymnotiforms under these conditions, which suggests E. meeki may be capable of similar reproduction — but this remains speculative for a species known only from its original description. Data on this species' breeding biology are sparse to nonexistent.
In the aquarium
Eigenmannia meeki has no known presence in the aquarium trade; it is a recently described, narrow-range species collected for scientific study rather than the ornamental market. Any care guidance must therefore be drawn from its close relative, the commonly traded glass knifefish (Eigenmannia virescens), with the caveat that it may not transfer precisely.
Were it ever kept, the general expectations for glass and rattail knifefishes would apply: warm, soft to moderately mineralised, near-neutral water; dim lighting and cover to suit a nocturnal, electrosensory fish; and particular caution with medications and water quality, since the group is scaleless and correspondingly sensitive to ammonia, nitrate, and copper-based treatments. As with all Eigenmannia, a shoal rather than a lone individual would likely reduce stress, mirroring how the more familiar glass knifefish is typically kept. None of this is confirmed for E. meeki specifically.
Conservation
Eigenmannia meeki has not been formally assessed by the IUCN Red List; its status is Data Deficient in the absence of a full evaluation. Described from a single river system in a part of Central America that has seen relatively limited ichthyological survey work, its broader distribution, population size and trend are essentially unknown.
As a narrow-range endemic — so far recorded only from the Río Pucuro within the Río Tuíra basin — it fits the general pattern among gymnotiforms in which single-river species carry more conservation uncertainty than widespread genus-mates, since localized habitat change, deforestation or water pollution in one drainage could disproportionately affect the entire known population. No specific threats have been documented for this species, and further survey work would be needed before its conservation status could be meaningfully assessed.