Taxonomy & naming
Distichodus polli was formally described in 2019 by Abwe, Snoeks, Chocha Manda and Vreven in the journal Ichthyological Exploration of Freshwaters, based on specimens from the southern Congo basin. The type locality is the Lulua River, part of the Kasai basin in the Democratic Republic of Congo. It belongs to the family Distichodontidae within the order Characiformes, a family of African characins that also includes the citharinids and that sits alongside — but taxonomically apart from — the South American piranhas, pacus and silver dollars.
As a species named only in 2019, D. polli has not yet accumulated the depth of literature, common names or aquarium history that older, more widely distributed Distichodus species have; much of what can be said about it with confidence is inferred from the genus rather than documented for the species itself, and that gap is noted throughout this article rather than filled with guesswork.
Morphology
Distichodus as a genus shares a recognisable body plan: an elongated, laterally compressed body, a small terminal-to-subterminal mouth adapted for grazing rather than seizing prey, and a row of small, close-set teeth suited to cropping plant material. Across the genus, adult size varies enormously by species — from around 2 in to as much as 30 in in the largest, D. sexfasciatus — which makes size a genus-level trait rather than something that can be assumed for any one member.
A specific maximum length for Distichodus polli is not established in the available record. Given its description from a relatively modest river system and its status as a distinct, newly recognised species rather than a synonym of one of the larger, long-known Congo Distichodus, some caution is warranted before assuming it reaches the scale of the genus's biggest species — but without a documented figure, this article does not assign one.
Habitat
Distichodus polli is known from the southern Congo basin, with its type locality in the Lulua River of the Kasai basin, Democratic Republic of Congo — a river system carrying the warm, often soft and tannin-influenced water typical of Congo basin tributaries. As with size, detailed habitat data specific to this species — depth preference, substrate association, seasonal movement — has not been established in the sources available for this article.
More broadly, the genus Distichodus is a Congo-basin-centred group (with some species extending into other African river systems such as the Niger and Nile), typically found in flowing river channels and floodplain habitats where plant growth and detrital material support their grazing diet.
Feeding
Distichodus as a genus are herbivorous to omnivorous grazers: species documented in the literature take plant leaves and stems as a dietary staple, supplemented with smaller amounts of worms, crustaceans and insects. This plant-forward diet is a defining trait of the genus and distinguishes Distichodus sharply from predatory characins.
No species-specific feeding study has been located for D. polli, so its diet is inferred from the genus rather than confirmed directly — but there is no reason to expect this species departs from the Distichodus pattern of needing a plant-heavy diet supplemented with modest protein.
Mating
No courtship or spawning behaviour has been documented for Distichodus polli specifically. Across the genus and the wider family Distichodontidae, reproductive biology is poorly studied relative to South American characins, and detailed accounts of pairing, courtship displays or spawning triggers are largely absent from both the scientific and aquarium literature.
Breeding
Distichodus, like the related citharinids, are egg-scattering characins with no parental care, but the genus is rarely if ever bred in the home aquarium — a pattern that holds across essentially every species that has reached the hobby. For Distichodus polli specifically, no aquarium or captive breeding has been documented; as a species described only in 2019 and apparently absent or nearly absent from trade, there is no established breeding record to report.
Given the genus's difficulty and D. polli's recency and rarity, prospective keepers should not expect this to be a species that can be bred at home; this article reports that honestly rather than inventing a spawning mode that has not been observed.
In the aquarium
Distichodus polli is not established in the aquarium hobby. It was described too recently, and from too specific a location, to have built any meaningful captive-care record, and no dedicated care guide was found among aquarium hobby sources. Because the genus spans everything from compact grazers to the meter-approaching D. sexfasciatus, and this species' adult size is not documented, it would be irresponsible to recommend a tank size or stocking plan without a real size figure to work from.
What can be said, drawn from the genus as a whole: Distichodus are plant-eaters that will graze soft aquarium vegetation, so any tank housing a Distichodus should be planted with that grazing pressure in mind, and diet should include a substantial vegetable component alongside modest protein. Anyone who does encounter D. polli in the trade should treat it as an unknown quantity requiring research and caution rather than a settled, well-understood aquarium fish.
Conservation
Distichodus polli has not been assessed by the IUCN Red List; its conservation status is Not Evaluated. This is unsurprising for a species described only in 2019 — formal Red List assessment typically lags well behind initial description, particularly for narrowly distributed African freshwater fishes.
As a species known from a specific southern Congo basin locality (the Lulua River, Kasai basin), it shares the general conservation context facing Congo basin freshwater fish: localised endemics can be vulnerable to habitat pressures such as sedimentation, deforestation and water development even where no formal assessment yet exists. No specific threats to D. polli have been documented, and this article does not speculate beyond that.