Taxonomy & naming
Eigenmannia camposi was described in 2020 by Herrera-Collazos, Galindo-Cuervo, Maldonado-Ocampo and Rincón-Sandoval in Neotropical Ichthyology, based on a holotype collected from the Magdalena river at Honda, Tolima, Colombia. 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 they sit apart from almost every other aquarium group: they are defined by an electric organ that runs the length of the body and by a greatly elongated anal fin used for locomotion, rather than a normal tail. The Catalog of Fishes (Eschmeyer, CAS) is the authority for the valid name.
The species was placed within the Eigenmannia trilineata species group, a cluster of similar, striped glass knifefishes that had previously been treated as a single wide-ranging species before closer anatomical work began splitting it by river basin. E. camposi is distinguished from its closest relatives by details of dentition and head proportions — the describing paper counted 27 premaxillary teeth arranged in three to four rows, and used suborbital depth (30–37.7% of head length) as one of the characters separating it from E. trilineata itself. The epithet honours Dr. Ricardo Campos-da-Paz of the University of São Paulo, recognising his contributions to the study of gymnotiform fishes. As with other Sternopygidae, it should not be confused with the unrelated Asian featherback and clown knifefishes (Chitala, Notopterus), which merely share the general "knifefish" body plan by convergence.
Morphology
Eigenmannia camposi has the classic glass-knifefish build: a slender, laterally compressed body that tapers to a fine point at the tail, with an elongated anal fin running along almost the entire underside and no dorsal fin at all. The type series ranges from a 5.5 in holotype up to about 8.5 in in total length, giving a sense of adult size for the species. Like its relatives, the body is thin enough to appear semi-transparent in life, a trait that gives the genus its common name of "glass knifefish," though the describing paper's own measurements focus on meristic and skeletal characters rather than colour pattern.
Running beneath the skin is the electric organ that defines the order, paired with electroreceptor pores scattered over the head and body that pick up distortions in the fish's own electric field. E. camposi produces a wave-type electric organ discharge — a continuous, near-sinusoidal signal rather than the intermittent pulses used by some other gymnotiform families — consistent with its placement in the E. trilineata group. The species is scaleless, a feature shared across the family that has real consequences for how sensitive it is to water quality and medication in captivity.
Habitat
Eigenmannia camposi is known from the lower Atrato basin and the upper and middle Magdalena and Cauca river basins in Colombia — a trans-Andean drainage system distinct from the Amazon and Orinoco basins that hold most of its relatives. The type locality sits on the Magdalena river itself, near Honda in Tolima department. This places the species firmly within the Neotropics, but as a narrower-range endemic of a single Colombian river system rather than a continent-spanning species.
Detailed habitat data — depth, flow, substrate, water chemistry in the wild — has not been published for E. camposi specifically. Congeners in the same family are generally fish of flowing water, found among submerged roots, vegetation and sediment in warm, often turbid or tannin-stained rivers where an electric sense is more useful than eyesight. Given the shared biology of the group, E. camposi likely occupies similar river-margin and channel habitat within its Magdalena–Cauca–Atrato range, but this should be read as an inference from its relatives rather than a documented fact for this species.
Feeding
No dietary study has been published for Eigenmannia camposi. Glass knifefishes as a group are nocturnal micro-predators, foraging after dark for small invertebrates — aquatic insect larvae, worms and tiny crustaceans — located largely through electrolocation rather than sight, probing among roots, leaf litter and sediment where prey hides during the day.
In the absence of species-specific data, the safest statement is that E. camposi almost certainly follows this same pattern as a fellow member of the E. trilineata group. Aquarists keeping related Eigenmannia report that captive fish accept live and frozen meaty foods such as bloodworm and brine shrimp, fed after dark when the fish become active, but this is drawn from care experience with congeners rather than from any published account of E. camposi itself.
Mating
As in other wave-type gymnotiforms, courtship in Eigenmannia is thought to be mediated partly through the electric organ discharge itself — genus-mates of E. camposi are the classic subjects of neuroscience work on the jamming avoidance response, in which two fish with similar discharge frequencies each shift their own frequency apart to avoid interference, and discharge frequency in the genus is known to differ between males and females in several species. Whether E. camposi shows the same sex-linked frequency difference and courtship signalling has not been documented; this is an inference from the wider genus, not a finding specific to this species.
No observations of courtship behaviour, spawning approach or mate selection have been published for E. camposi. Data are sparse to the point that nothing more specific can be said without over-reaching beyond what is actually known.
Breeding
There is no published breeding record for Eigenmannia camposi, in the wild or in captivity. Members of the genus Eigenmannia are egg-layers that scatter adhesive eggs among plant roots and fine vegetation, generally in warm, soft water, and some aquarists have reported spawning success with congeneric glass knifefish by simulating a wet-season rise in water level alongside a drop in pH and a slight cooling — the kind of cue thought to trigger breeding in the wild. Eigenmannia as a genus is considered one of the more approachable gymnotiforms to breed relative to other knifefish groups, but reports remain scattered hobbyist accounts rather than controlled studies.
For E. camposi specifically, there is no parental care documented, consistent with the pattern across Sternopygidae of eggs left among vegetation with no guarding. Given how recently the species was described and how little has been published beyond the original taxonomic paper, breeding in this particular species should be treated as essentially undocumented.
In the aquarium
Eigenmannia camposi is not an established aquarium fish — it was described from museum material in 2020 and there is no evidence it is currently available in the ornamental trade, unlike its far more commonly kept relative E. trilineata. Any care guidance has to be extrapolated from the genus. Glass knifefish in the trade are generally kept in dimly lit tanks with driftwood, caves and dense planting to give them secure daytime cover, over soft substrate in low-flow areas, and they do best in a small group rather than alone.
Being scaleless, Eigenmannia species need particular care with medications — copper-based treatments should be avoided and doses of other medications reduced — and they are sensitive to ammonia and nitrate, so mature filtration and stable, warm, soft, near-neutral to slightly acidic water matter more than they would for a scaled fish. As a nocturnal electroreceptive predator, this genus is not reliably safe with small tankmates such as tiny fish or shrimp after dark, even though it appears peaceful toward similarly sized fish by day. Should E. camposi ever enter the hobby, it would be reasonable to expect it to need the same conditions as its congeners; for now, keepers are far more likely to encounter E. trilineata or other established Eigenmannia species.
Conservation
Eigenmannia camposi has not been separately evaluated by the IUCN Red List; its status is best treated as Data Deficient given how recently it was described and how little has been published on its population size, trends or specific threats. It is known only from the lower Atrato basin and the upper/middle Magdalena and Cauca basins in Colombia, a river system that has experienced significant habitat pressure from damming, pollution, mining and land-use change over recent decades.
As a narrow-range endemic restricted to a single trans-Andean drainage rather than a continent-spanning species, E. camposi fits the general pattern among gymnotiforms where the vulnerable species are the single-basin specialists, not the widespread generalists. No specific conservation programme or monitoring targets this species; its outlook is tied to the broader condition of the Magdalena–Cauca system, one of Colombia's most heavily used river basins.