Taxonomy & naming
Neoheterandria cana was described by Seth Eugene Meek and Samuel Frederick Hildebrand in 1913, during their landmark survey of the freshwater fishes of Panama. The parenthetical authority — (Meek & Hildebrand, 1913) — indicates that the species was originally placed in a different genus and later moved into Neoheterandria, the standard signal of a subsequent recombination. Eschmeyer's Catalog of Fishes treats Neoheterandria cana as the valid name within the family Poeciliidae, the New World livebearers, in the subfamily Poeciliinae.
The genus name Neoheterandria is built from Greek roots: neos, "new," combined with heteros, "other" or "different," and andros, "male" — literally a "new Heterandria," marking the genus as a relative of the dwarf livebearer genus Heterandria with its own distinct males. The specific epithet cana refers to the Cana region of the Río Tuira drainage in the Darién of eastern Panama, the area from which the type material was drawn. The English name "Cana toothcarp" follows directly from that geography.
Neoheterandria is a small genus of Central American dwarf poeciliids; its best-documented member in the hobby is Neoheterandria elegans, the orange "Tiger Teddy" of Colombia, with N. tridentiger and N. cana far less familiar. Because N. cana has been so little collected and almost never kept, its taxonomy rests largely on the original description and museum specimens rather than on any modern revisionary or molecular study; firm details beyond the valid name and broad placement are data-sparse.
Morphology
Neoheterandria cana is a true dwarf livebearer. FishBase records a maximum length of about 1 in for males or unsexed fish, with females reaching roughly 1.5 in — the larger, deeper-bodied sex typical of poeciliids. Even at the upper end this is a very small fish, smaller than a guppy, and its scale places it among the tiniest of the live-bearing toothcarps.
Like other members of its subfamily the species is sexually dimorphic, the males being smaller and slimmer and the females larger and rounder, particularly when carrying young. The single most diagnostic male feature of any poeciliid is the gonopodium, a rod-like intromittent organ formed from modified rays of the anal fin and used to inseminate the female; in Neoheterandria this structure, together with overall body proportions and fin-ray counts, underpins the genus diagnosis. Detailed colour and meristic descriptions for N. cana specifically rest on the original 1913 account and museum material, and beyond the size figures and the general dwarf-poeciliid body plan the species-specific morphology is not well documented in modern sources.
Habitat
Neoheterandria cana is native to Panama, in the Pacific-slope drainages of the eastern part of the country. The type material comes from the Cana area of the Río Tuira system in the Darién, a remote, forested region of lower Central America, and the species' known range appears to be narrow and centred on these eastern Panamanian freshwaters. FishBase classifies it as a freshwater, pelagic, tropical species.
No dedicated habitat study of N. cana exists, so its ecology is inferred from its distribution and from the genus. Neoheterandria are small fishes of shallow, slow-moving, often vegetated tropical streams and their margins — the kind of warm, low-gradient lowland and foothill waters that characterise the Darién drainages. The combination of a restricted, little-surveyed range and very few collections is exactly what leaves the species poorly known and, in conservation terms, Data Deficient. Specific figures for the temperature, pH and hardness of its native waters are not documented; only the broad tropical-freshwater envelope of the region can be stated with confidence.
Feeding
There is no published dietary study of Neoheterandria cana. FishBase lists only an estimated trophic level of around 3.0, derived from relatives rather than from gut-content analysis of this species, which places it broadly among the small omnivores and micro-predators.
By analogy with other dwarf poeciliids of shallow Central American streams, N. cana is expected to feed on small invertebrates, insect larvae, micro-crustaceans, and associated algae and detritus taken from the water column and from plant and substrate surfaces. Tiny livebearers of this kind are typically continuous grazers on whatever small live food is available. Because the species is essentially absent from the aquarium trade, there is no body of husbandry experience to refine this picture, and any account of its feeding remains an inference from genus-level natural history rather than a documented fact.
Mating
Like all poeciliids, Neoheterandria cana reproduces by internal fertilisation rather than by spawning eggs into the water. The male transfers sperm to the female using the gonopodium, the modified anal fin that is the defining reproductive structure of the family; courtship and insemination occur while the eggs are still retained inside the female's body. This mode of reproduction is conserved across the subfamily Poeciliinae and can be stated with confidence for N. cana even though the species itself has not been observed breeding.
In dwarf livebearers generally, males pursue and display to females, and females are often able to store sperm internally, allowing successive broods to be produced from a single mating. Whether N. cana shows the elaborate courtship behaviour, sperm storage, or the superfetation — the simultaneous carrying of broods at different developmental stages — that occur in some other poeciliid lineages is not documented. No mating observations specific to this species have been published, so beyond the certainty of gonopodial, internal fertilisation the behavioural detail is data-sparse.
Breeding
Neoheterandria cana is a viviparous livebearer: after internal fertilisation the female carries the developing young and gives birth to free-swimming fry rather than laying eggs. This follows from its membership in the Poeciliidae and is consistent with its congeners, which are small lecithotrophic (yolk-nourished) livebearers that bear modest broods of fully formed young.
Species-specific reproductive data — gestation length, brood size, the frequency of broods, and whether superfetation occurs — have not been recorded for N. cana, and the pre-crawled sources explicitly caution against asserting figures that do not exist. In the closely related and better-studied Neoheterandria elegans, females produce small broods at frequent intervals and superfetation has been reported in the genus, so it is plausible that N. cana behaves similarly; this remains an analogy, not a measurement. FishBase rates the species' resilience as high, with an estimated population doubling time of under fifteen months, which is consistent with the rapid, continuous reproduction typical of small livebearers even though the underlying brood data for this species are absent.
In the aquarium
Neoheterandria cana is effectively unknown in the aquarium hobby. Searches of specialist livebearer and biotope sources turned up care and breeding material only for its congeners — chiefly the orange "Tiger Teddy," Neoheterandria elegans — and nothing specific to N. cana. The species appears essentially absent from the trade, and there is no documented body of husbandry experience to draw on.
Any keeping recommendations would therefore have to be extrapolated from related dwarf poeciliids: a small, warm, well-planted aquarium with gentle filtration and stable tropical water, fine live and prepared foods, and quiet tankmates that will neither outcompete nor prey on so tiny a fish. Those are reasonable expectations for a dwarf livebearer of shallow Central American streams, but they are inference rather than established practice for this species. In honest terms, N. cana is a museum-and-records fish rather than an aquarium fish, and its specific care requirements are undocumented.
Conservation
Neoheterandria cana is assessed as Data Deficient (DD) on the IUCN Red List, in an assessment dated 2 October 2019. The Data Deficient category means there is not enough information on the species' distribution, population or trends to evaluate its risk of extinction — not that it is necessarily safe, but that it is too poorly known to classify. For a narrowly distributed, rarely collected dwarf poeciliid of eastern Panama, this is an unsurprising outcome.
The practical conservation concern for such a species is the vulnerability that comes with a small, localised range in a region subject to deforestation, agriculture and other pressures on freshwater habitats: a fish known from few collections in one drainage system can be at risk even when no decline has been measured, simply because so little is known. The clearest conservation message is the need for basic survey and natural-history work to establish where N. cana actually occurs and how its populations are faring. Until that is done, its status will remain Data Deficient, and statements about its abundance or trajectory should be made with corresponding caution.