Taxonomy & naming
Clarias dhonti was described by the Belgian-British ichthyologist George Albert Boulenger in 1920, from material collected during the Belgian East African Expeditionary Corps' survey of the Congo–Tanganyika watershed. The type locality is Kabeke Village on the Niemba River. It belongs to the family Clariidae, the airbreathing or walking catfishes, and to the genus Clarias, a large Afro-Asian genus of more than 60 species.
The species epithet honours G. Dhont-De Bie, a member of that expeditionary corps. Clarias has been heavily revised over the past century, and older literature on Congo basin catfishes sometimes files similar species under now-obsolete combinations; C. dhonti has remained in Clarias since its description and is treated as the valid combination by the Catalog of Fishes.
Morphology
Clarias dhonti has the classic walking-catfish silhouette: an elongate, cylindrical body, a broad, dorsally flattened head with a broadly rounded snout, and laterally placed eyes. The dorsal fin is very long, with 69–80 soft rays and, unusually for the genus, no true dorsal spine; the anal fin is similarly long-based with 59–64 soft rays, and both run most of the length of the body toward a small, rounded caudal fin.
Like all Clarias it is scaleless, its skin covered instead by a protective mucus layer, and it carries stiff, serrated pectoral spines that can be locked erect. Maximum recorded size is 7.5 in total length, considerably smaller than well-known aquaculture Clarias such as C. gariepinus or C. batrachus, but the spines, air-breathing labyrinth-like organ and general biology of the genus are unchanged at this smaller scale.
Habitat
The species is known only from the Niemba River, a tributary of the Luvua River in the upper Congo basin, and the Koki River just west of Lake Tanganyika, both in the Democratic Republic of the Congo. It is a demersal freshwater fish, living on or near the bottom of these river systems in the Congo–Tanganyika watershed.
Detailed water-chemistry data for the Niemba and Koki rivers has not been published in the sources available here; broadly, Clarias species across the Congo basin tolerate a wide range of conditions, including warm, often oxygen-poor water, which the genus's accessory air-breathing organ is adapted to handle. Specific pH and hardness figures for this species are data sparse.
Feeding
Clarias dhonti is, like its relatives, a nocturnal predator. Clarias as a genus are opportunistic piscivores that take any fish or invertebrate small enough to swallow, hunting mostly after dark and relying on barbels and a keen sense of smell rather than eyesight in the murky water and low light they favour.
In the aquarium this translates directly: it accepts large meaty foods such as whole fish, prawns, and sinking pellets, and will not distinguish between offered food and a tankmate that fits in its mouth. Any companion fish must be too large to be swallowed.
Mating
No species-specific courtship or spawning behaviour has been documented for Clarias dhonti in the sources available here. Across the genus, Clarias species typically pair up in flooded margins or slow water during the rainy season, with the male clasping the female to stimulate egg release; eggs are scattered over vegetation or the substrate rather than laid in a nest. Whether this pattern applies in detail to C. dhonti in its native rivers is not documented — data sparse.
Breeding
Large and commercially important Clarias species are spawned at farm scale using hormone induction, since captive pairs rarely spawn spontaneously once past a modest size; there is no record of Clarias dhonti being bred in a home aquarium. Given its restricted native range and lack of any established aquarium trade, it should be treated as essentially not bred in captivity — any specimens in the hobby, where they exist at all, are wild-collected rather than farm-raised offspring.
In the aquarium
Clarias dhonti is rarely if ever seen in the aquarium trade, but the genus's care requirements are consistent and worth stating plainly. Even at a comparatively modest adult size of 7.5 in total length, this is an air-breathing predatory catfish that needs a tight-fitting lid (Clarias are notorious escape artists that can survive out of water for extended periods), access to the surface to gulp air, and dim lighting with caves or cover for daytime retreat, since it is active mainly at night.
Two handling points matter for every Clarias: the skin is scaleless, so medication — particularly copper-based treatments — should be dosed conservatively, often at half the labelled rate; and the pectoral spines are stiff, serrated, lockable and reported to carry venom in related Clarias species, capable of tangling in a net and jabbing the handler. Move this fish in a rigid container rather than a net. Tankmates must be robust and too large to be eaten, since this is an unapologetic predator. As with all Clarias, never release surplus fish — the genus is a well-documented invasive outside its native range.
Conservation
The IUCN Red List assesses Clarias dhonti as Least Concern, based on a 2022 assessment. This sits alongside a caveat worth noting: its known range is narrow, restricted to the Niemba and Koki rivers in the Congo–Tanganyika border region, and localized single-river or two-river distributions of this kind carry more risk than the Least Concern label alone conveys.
There is no established aquarium trade or aquaculture pressure specific to this species in the sources available here, so its main long-term risks are the general pressures on Congo basin tributaries — habitat change, water quality, and the cumulative effect of activity across the wider Luvua and upper Congo drainage — rather than collection for the hobby.