Taxonomy & naming
Cyphomyrus discorhynchus belongs to the order Osteoglossiformes, the bonytongues — a scattered, deep-time radiation of freshwater fishes found today across South America, Africa, Southeast Asia and Australasia, and named for a toothed bone on the floor of the mouth that bites against a toothed pad on the roof. The family Mormyridae, the elephantnoses and mormyrids, is the order's exclusively African branch and by far its most species-rich, with roughly 200 species defined as much by their electric organ discharge (EOD) as by their outward appearance. This species was first described by the German naturalist Wilhelm Peters in 1852; the parenthetical authority "(Peters, 1852)" records that it was originally placed in a different genus (historically Mormyrus) before later being assigned to Cyphomyrus, a smaller genus separated out from the larger Mormyrus.
The genus Cyphomyrus combines the Greek kyphos, "bent" or "humped", with the recurring mormyrid suffix -myrus, from myros, "eel" — an allusion to the somewhat arched head-and-back profile that distinguishes Cyphomyrus from its close relative Mormyrus. The species epithet discorhynchus joins the Greek diskos, "disc", with rhynchos, "snout", describing the fish's distinctively rounded, disc-shaped snout — the field mark noted directly in the species' original diagnosis and still one of the most reliable ways to tell it apart from superficially similar mormyrids in the same rivers.
Morphology
Cyphomyrus discorhynchus has the deep-bodied, laterally compressed build typical of the larger mormyrids, with a rounded, blunt snout (the source of its epithet), an eye set noticeably above the level of the mouth, and a fleshy bulge on the chin rather than the long, mobile, worm-like schnauzenorgan carried by the true elephantnoses of the genus Gnathonemus. That distinction matters for identification: this is a "parrotfish"-type mormyrid with a rounded head profile, not a probing, trunk-nosed forager.
FishBase records a maximum size of about 12.2 in standard length and a weight of up to roughly 1.1 kg, making it a substantially larger fish than many of the small, slender mormyrids traded as "elephantnoses"; aquarium specimens offered in the hobby are typically well short of that maximum. As in other mormyrids, the defining organ is internal rather than external: a specialised electric organ in the caudal peduncle generates a continuous, low-voltage, pulse-type field, processed by a brain with one of the highest brain-to-body mass ratios of any fish, built around an oversized cerebellum dedicated to handling the constant stream of electrosensory information.
Habitat
Cyphomyrus discorhynchus is unusually wide-ranging for a mormyrid, recorded from the Cunene, Okavango/Cubango, Buzi, Pungwe, Save and Zambezi river systems, the Malagarasi River, Lake Rukwa, and Lakes Tanganyika and Malawi — a span across southern and East Africa that touches Angola, Namibia, Botswana, Zimbabwe, Mozambique, Zambia, Malawi and Tanzania. Within that range it is a freshwater, demersal fish and a nocturnal shoaler, associating in groups rather than living the solitary life of some smaller mormyrids.
It favours soft bottoms with fringing aquatic vegetation and the calmer margins of its river and lake systems — sheltered bays, lagoons and swamps — rather than fast, open channels. FishBase field records put its water around 72–75 °F, cooler than the equatorial West African rivers many other mormyrids call home, consistent with the more southerly, higher-elevation reach of the Zambezi and rift-lake basins it inhabits.
Feeding
As with other mormyrids, Cyphomyrus discorhynchus almost certainly locates its food by electrolocation rather than sight, probing the soft, vegetated bottoms and sheltered margins it favours after dark for small aquatic invertebrates rather than hunting in open water. Detailed, species-specific data on its wild diet are sparse in the cited sources, in keeping with how little fine-grained natural-history work exists for most mormyrids outside a handful of well-studied genera.
In the aquarium, hobby guidance for elephantnose-type mormyrids more broadly calls for a protein-rich diet of live or frozen foods — bloodworm, blackworm, brine shrimp and tubifex are typical staples — reflecting the largely carnivorous, invertebrate-based feeding these fish are believed to rely on in the wild.
Mating
Courtship and pairing in Cyphomyrus discorhynchus are not documented in the cited sources. As in other mormyrids, the electric organ discharge is thought to play a role in mate recognition and courtship signalling, since EOD waveforms are known to differ between the sexes in related species, but no specific account of this species' courtship behaviour has been published.
General mormyrid biology points to seasonal, rain- or flood-cued spawning, but whether that pattern holds for this particular species, and what its spawning-site preferences or courtship displays look like in the wild, remains unrecorded — an honest gap rather than a detail to guess at.
Breeding
Breeding in Cyphomyrus discorhynchus is essentially unknown. No wild breeding details are recorded in the cited sources, and captive breeding of this species is, by every available account, essentially unachieved — consistent with mormyrids generally, which are seasonal, flood-triggered spawners whose reproductive behaviour is poorly understood and only rarely, if ever, replicated in aquaria.
Parental care is likewise undocumented for this species; some mormyrids are thought to guard eggs among plants or roots, but there is no confirmed description of that behaviour here. Aquarists should treat Cyphomyrus discorhynchus as a wild-collected species rather than one with any established captive breeding protocol.
In the aquarium
Cyphomyrus discorhynchus is best kept solitary: hobby guidance for this and closely related elephantnose-type mormyrids notes that multiple individuals housed together can stress one another through overlapping electric organ discharges, so a single fish rather than a group is the standard recommendation. Given its documented size — to roughly 12.2 in and over a kilogram in the wild — it needs generous swimming space well beyond the smaller mormyrids typically sold as "elephantnoses"; hobby sources suggest a minimum in the region of 50–74 US gal as a starting point, and a larger, established fish will want more.
Provide dim lighting, soft sand, driftwood and caves for daytime cover, and dense planting to soften the tank into something closer to its natural sheltered-bay and swamp habitat; it is most active after dark. Water should run neutral to slightly acidic, and — as with every mormyrid — this is a scaleless-adjacent, medication-sensitive fish that cannot tolerate copper-based treatments, so gentle, copper-free dosing and stable water quality matter more here than with a typical community fish.
Conservation
The IUCN Red List assessed Cyphomyrus discorhynchus as Least Concern in 2022. This tracks with its unusually broad distribution across multiple independent river and lake systems in southern and East Africa — the Zambezi, Okavango, Save and allied basins plus Lakes Tanganyika, Malawi and Rukwa — a range few mormyrids can match, and no CITES listing is recorded for the species.
Population-trend data specific to this species are sparse, as they are for most mormyrids outside a few intensively studied genera, so the Least Concern status rests primarily on range breadth rather than a detailed count. The general regional pressures facing its basins — damming, siltation and shoreline habitat loss around the lagoons and swamps it favours — are the relevant long-term watch points rather than any documented decline specific to this species.