Taxonomy & naming
Distichodus noboli was described by the Belgian-British ichthyologist George Albert Boulenger in 1899, based on material from the upper Congo River basin. It belongs to the family Distichodontidae — the African distichodontid characins — within the order Characiformes, and to the genus Distichodus, which the Catalog of Fishes (Eschmeyer, California Academy of Sciences) recognises as the authority for the valid name and places among a genus of several dozen African species ranging from small, peaceable grazers to the large, boldly banded D. sexfasciatus and D. lusosso kept widely in the aquarium trade.
The species epithet "noboli" is not a Latin descriptor but a local vernacular name recorded from the upper Congo at the time of Boulenger's description, a naming pattern not uncommon among characins collected during the great African river surveys of the late nineteenth century. There is no evidence in the available record of a more recent taxonomic revision or synonymy affecting this species; it should be treated under its original combination, Distichodus noboli.
Morphology
Distichodus noboli shares the characteristic distichodontid body plan: an elongated, laterally compressed silhouette with a small, subterminal mouth set low and angled for grazing rather than seizing prey, and a slender caudal peduncle leading to a forked tail. FishBase records a maximum published length of 7.5 in total length, a modest size within a genus whose best-known members (D. sexfasciatus, D. lusosso) can approach or exceed 31.5 in — a distinction worth stressing because the genus name alone tells a prospective keeper very little about adult size.
Detailed published description of colour pattern and fin structure is sparse in the sources available for this account; the genus generally shows silvery flanks with variable dark barring or striping in many species, and this account does not assert a specific pattern for D. noboli beyond what is documented. No external sexual dimorphism has been documented for this species in the available literature.
Habitat
The species occupies the middle and upper Congo River basin, with records from the Democratic Republic of the Congo and the Republic of Congo. Its type locality is the upper Congo River basin, and it is described as a freshwater, pelagic species that moves in shoals through open and structured water in this system, in keeping with the general shoaling habit of many smaller Distichodus.
Detailed water-chemistry data specific to D. noboli's collection sites is not available in the sources for this account; broadly, the middle Congo basin runs warm, and other Congo-basin distichodontids are typically kept in soft to moderately hard, mildly acidic to neutral water. Prospective keepers should treat any specific numeric range as an aquarium husbandry approximation rather than a documented field measurement for this species specifically — see Facts and "In the aquarium" for the figures used here.
Feeding
Distichodus noboli is an omnivore with a herbivorous tendency, consistent with its genus. FishBase husbandry notes describe it taking flakes, pellets and fresh or frozen foods readily, with young fish needing a more protein-rich diet than adults as they grow. As with other Distichodus, plant matter forms a significant part of the natural diet, which is the direct cause of its poor compatibility with live-planted aquaria.
In practice this means a varied diet built around vegetable-forward foods — blanched vegetables, spirulina-based flakes or pellets, and algae wafers — supplemented with occasional protein such as bloodworm or brine shrimp, especially for juveniles. Keepers should not expect this species to leave ornamental plants alone; it will graze soft-leaved and even some tougher species given time.
Mating
No courtship behaviour has been documented for Distichodus noboli in the sources available for this account. The genus as a whole is not well studied in this respect; most Distichodus and related citharinids are understood to be egg-scatterers with no pair-bonding or nest-building behaviour recorded, but specific observations of courtship, sex differences, or spawning triggers for this species are not available and this account does not invent them.
Breeding
Distichodus noboli has no documented breeding record in the aquarium, and this account follows the cache and broader genus pattern rather than speculating. African distichodontids and their citharinid relatives are, as a group, egg-scatterers that show no parental care, and members of the genus Distichodus are widely reported as very difficult to induce to spawn in a home aquarium — most individuals in the trade are wild-caught or produced through hormone-assisted commercial spawning rather than home breeding.
Given the absence of species-specific breeding data, keepers should not expect to reproduce this species in a typical home setup; anyone attempting it would be working essentially without a documented precedent for D. noboli itself.
In the aquarium
Distichodus noboli is described in husbandry sources as peaceful in a community setting, though males can become territorial with one another, and it is genuinely a shoaling fish — sources recommend keeping it in a group in a tank of at least 160 US gal, sized for a school rather than a single specimen. At a maximum of around 7.5 in, it is far more manageable in a home aquarium than the larger Distichodus species, but it still needs real swimming room and the company of its own kind to settle.
The single most important compatibility note is that this species is incompatible with live plants: it will graze soft vegetation persistently, so keepers wanting a planted look should rely on hardy, unpalatable species, heavy rockwork, or artificial decor instead. Diet, tankmate size, and water quality should otherwise follow standard peaceful-community practice for a mid-sized African characin — strong filtration for a shoal's bioload, and tankmates too large or too fast to be seen as a target.
Conservation
Distichodus noboli is assessed by the IUCN Red List as Least Concern, an assessment dated 16 February 2009. This reflects a lack of documented major threats to the species within its Congo basin range rather than an exhaustive population study; the species is not flagged with any specific conservation concern in the sources reviewed for this account.
As with many Congo-basin fish, broader pressures on the basin — including habitat disturbance, sedimentation and regional fishing pressure — are relevant long-term context even though D. noboli itself is not currently classed as threatened. The aquarium trade appears to rely at least in part on wild-collected specimens, consistent with the absence of any documented captive-breeding pathway for the species.