Taxonomy & naming
Citharinus citharus was described by Étienne Geoffroy Saint-Hilaire in 1809, based on material collected during the Napoleonic expedition to Egypt, making it one of the earliest-described African freshwater characiforms. It is the type species of the genus Citharinus and belongs to the family Citharinidae — the citharinids or "African moon fishes" — within the order Characiformes, a family confined entirely to Africa and distinct from the related Distichodontidae (the distichodins) with which it shares the broader African characin lineage.
Older literature has recognised two subspecies, C. c. citharus and C. c. intermedius, though current authorities including the Catalog of Fishes (Eschmeyer, California Academy of Sciences) and the Catalogue of Life list Citharinus citharus as the accepted valid combination without noting any superseded genus assignment. The genus Citharinus itself contains several broadly similar deep-bodied grazing species across African river systems, and field identification between them can be difficult without close examination.
Morphology
Citharinus citharus has a strongly compressed, deep, almost disc-shaped body — the resemblance to a full moon or a round stringed instrument (a cithara) is the likely inspiration for both its common and scientific names. The head is small relative to the body, with a small, subterminal, downturned mouth adapted for grazing rather than seizing prey, and the body is covered in fine silvery scales that give the fish a bright, reflective flank in life.
FishBase records a maximum published size of 23 in standard length, with published weights reaching up to about 7 kg, making this one of the larger fish in the African characin group covered here. Fins are unremarkable — a small adipose fin typical of characiforms is present behind the dorsal fin — and overall the silhouette is unmistakably that of a grazing, schooling fish rather than a predator: rounded, laterally flattened, and built for stability over a soft riverbed rather than bursts of speed.
Habitat
The species has a wide distribution across West, Central and East African river basins, recorded from the Gambia, Senegal, Niger, Volta and Ouémé river systems, the Chad basin, the Nile basin, and east into Lake Turkana and Lake Albert. It typically inhabits the main channels and floodplains of large, slow-moving rivers and associated lakes, often moving onto seasonally flooded plains to feed as water levels rise, in a pattern shared with several other large African riverine characins.
Water across this range is generally warm, in the broad vicinity of 72–82 °F reported for the Nile/Sudan region populations FishBase draws on, and typically turbid, silt-laden river or floodplain water rather than the soft blackwater conditions associated with South American characins. Specific pH and hardness data for wild populations were not found in the sources consulted here.
Feeding
Citharinus citharus is a detritivore/herbivore grazer, and FishBase assigns it a low trophic level (around 2.0) consistent with a diet dominated by algae, biofilm (Aufwuchs) and organic detritus scraped from submerged surfaces and riverbed silt. Gut-content examinations cited by FishBase describe stomachs containing large volumes of largely indigestible plant material — chitin, cellulose and lignin fragments — reflecting a feeding strategy built around processing high volumes of low-quality food rather than selecting nutrient-dense items.
In the aquarium this translates into a fish that grazes constantly on algae and biofilm on any available surface, and hobbyist sources describe it accepting a mixed diet of dried, frozen and live foods alongside its natural grazing behaviour. Vegetable-forward foods — algae wafers, blanched greens, spirulina-based flakes or pellets — should form the bulk of any prepared diet, with only modest protein supplementation.
Mating
No courtship behaviour, pairing or sexual dimorphism for Citharinus citharus was found in the sources consulted for this article. Like many large, wide-ranging African riverine characins, its reproductive behaviour in the wild is not well documented in the literature available here, and no external means of distinguishing males from females is reported. This is a case where the honest answer is that the data is sparse rather than absent by omission.
Breeding
Citharinus citharus is a total spawner: FishBase records it as releasing all of its eggs in a single event rather than in repeated batches, with no parental care of eggs or fry reported — consistent with the broader pattern among African citharinids and distichodins, which are egg-scatterers rather than nest-guarders. It is not a species that is bred or reported to be bred in home aquaria; its very large adult size, migratory, floodplain-linked spawning behaviour in the wild, and its role as a food fish rather than an ornamental species all make captive breeding impractical for hobbyists.
No details of spawning triggers, fecundity, egg or larval development were found in the sources consulted, and this article does not speculate beyond what is documented. Prospective keepers should assume this species is wild-collected or farmed for food rather than aquarium-bred.
In the aquarium
Citharinus citharus is rarely kept, and hobbyist sources are consistent that any attempt requires a genuinely large aquarium — one supplier recommends upwards of roughly 1,25 US gal (300+ US gallons) for even a small group, given the species' eventual size of close to 23.5 in and several kilograms. It is described as peaceful toward both conspecifics and other fish, making it compatible with other large, calm species in a suitably oversized community setup, but its size alone rules it out of the vast majority of home aquaria.
As a constant grazer it will pick over algae and biofilm on any available surface and is not considered a plant-shredder in the way some of its relatives are, though its bulk and appetite still call for a sturdy, open layout rather than a densely planted scape. A varied diet leaning toward vegetable matter — algae wafers, blanched vegetables, spirulina foods — supplemented with occasional meaty foods mirrors its natural grazing, low-trophic-level diet. Given its size and food-fish status across its native range, this is a species for public aquaria and specialist keepers with pond-sized systems rather than a typical home tank, and it should never be purchased on impulse by a keeper without the space to accommodate an adult.
Conservation
The IUCN Red List assesses Citharinus citharus as Least Concern, an assessment dated 24 April 2019, reflecting its very wide distribution across major West, Central and East African river and lake systems and the absence of an immediate, documented threat to the species as a whole. It supports substantial artisanal and commercial fisheries across its range — it is an important food fish in parts of the Nile, Chad and Niger basins — and that fishing pressure, while locally significant, has not been assessed as threatening the species range-wide.
As with many widespread African riverine fish, localised pressures from damming, water abstraction and habitat degradation in specific river systems are relevant long-term considerations even though they have not driven a change in the species' overall Red List status. No aquarium-trade-specific conservation concerns were found in the sources consulted; the species' role in the hobby is negligible compared with its importance as a food fish.