Taxonomy & naming
Stomatorhinus corneti was described by the Belgian-born ichthyologist George Albert Boulenger in 1899, one of numerous small Congo basin mormyrids he named around the turn of the century as part of his broader work on the fish fauna of the Congo. It is placed in the family Mormyridae, the elephantfishes, within Osteoglossiformes — the ancient order of bonytongues — and specifically in the genus Stomatorhinus, a group of small mormyrids distinguished from the trunk-nosed Gnathonemus and Campylomormyrus by a short, plain mouth set low on the head. The exact type locality is not established in the sources consulted for this account, and no synonymy or later revision of the name is documented here; the combination Boulenger established in 1899 is the one currently in use.
The genus name Stomatorhinus is built from the Greek stoma (mouth) and rhinos (nose, snout), describing the mouth-and-snout region that separates the genus from its more elaborately nosed relatives. The species epithet corneti honors Jules Cornet (1865-1929), a Belgian geologist, explorer and naturalist active in Central Africa in the same period as Boulenger's Congo fauna work and remembered as a founding figure of Congolese geology; the original description does not elaborate on the dedication beyond the name itself.
Morphology
Stomatorhinus corneti is a small mormyrid, reaching about 4 in in total length, which places it among the smaller members of a genus already made up of modest-sized fish. Like other Stomatorhinus species it has a laterally compressed body, a short head, and a small, underslung mouth set back from the tip of the snout rather than the elongated chin appendage carried by Gnathonemus and its relatives. Detailed morphometric data beyond overall length is not available in the sources used for this account.
As in every mormyrid, an electric organ near the base of the tail generates a weak, pulsed field that the fish reads through electroreceptors spread across its skin, using the sense for orientation and object detection in the low-visibility water typical of Congo basin streams and backwaters. In Stomatorhinus corneti the discharge is documented as steroid-sensitive and sexually dimorphic in waveform, meaning males and females produce measurably different pulses, though the fine structure of that difference is not detailed in the sources reviewed here.
Habitat
Stomatorhinus corneti is documented from the middle and lower reaches of the Congo River across the Democratic Republic of the Congo and the Republic of the Congo, including the Pool Malebo area where the river widens above Kinshasa and Brazzaville. FishBase lists it as a freshwater, demersal species of tropical lowland river habitat.
Specific data on substrate, current or water chemistry at the species' collection sites is not available in the sources consulted for this account. Conditions across the wider Congo basin range from clear and blackwater forest tributaries to turbid whitewater river channels, and no single description of any of these should be assumed to apply to Stomatorhinus corneti without confirmation.
Feeding
No species-specific dietary study of Stomatorhinus corneti was located for this account. Mormyrids in general are benthic invertebrate feeders that use their electric sense to locate small prey such as insect larvae, worms and tiny crustaceans hidden in mud, sand and leaf litter. The small, underslung mouth of Stomatorhinus corneti is consistent with that generalist bottom-feeding mode, but this is an inference drawn from the family rather than a documented fact for the species itself.
Mating
No account of courtship or mate recognition specific to Stomatorhinus corneti was located. Across mormyrids generally, the electric organ discharge is thought to carry information used in species and sex recognition and possibly in courtship, and the sexual dimorphism already documented in this species' EOD waveform is consistent with some role along those lines. No study of the species' actual mating behavior in the wild or in captivity is available in the sources reviewed for this account.
Breeding
Breeding biology in Stomatorhinus corneti is unrecorded. No wild spawning observations or aquarium breeding accounts for this species were found, and mormyrids as a family are bred in captivity only rarely; the few members of the family that reach the hobby at all are almost always wild-caught rather than farmed. Nothing about egg-laying, parental care or larval development can be stated for this species without inventing it.
In the aquarium
Stomatorhinus corneti has essentially no track record in the aquarium hobby. It is not a species offered through normal trade channels, and no husbandry account specific to it was located for this article. Anyone attempting to keep a small Stomatorhinus would need to follow the general precautions that apply to mormyrids as a group: soft sand for probing, dim lighting and ample cover to offset the weak eyesight these fish compensate for with electrolocation, and live or frozen invertebrate foods rather than flake, since mormyrids commonly ignore dried food. Mormyrids are also known for sensitivity to poor water quality and to many common aquarium medications, particularly those containing copper, so conservative dosing and slow acclimation matter more with this family than with most community fish.
Given the complete absence of a documented captive history for this species, none of the above should be read as tested advice for Stomatorhinus corneti specifically. It is a cautious extension of what is known to work for its relatives, not a record of what has worked for this fish.
Conservation
The IUCN Red List assessed Stomatorhinus corneti as Least Concern in 2009. No species-specific threats are detailed in the sources available for this account. As with other small Congo basin fish, broader long-term pressures on the basin — deforestation, siltation and rising human use of lowland forest streams — are the kind of general concern relevant to a species like this one, though none is documented as an active driver of decline for Stomatorhinus corneti specifically.