Taxonomy & naming
Myomyrus macrodon was described by the Belgian-British ichthyologist George Albert Boulenger in 1898. It belongs to the family Mormyridae, the elephantnoses and mormyrids, within the order Osteoglossiformes — the bonytongue fishes, one of the oldest surviving branches of the teleosts. The order's living members are scattered across South America, Africa, Southeast Asia and Australasia by deep geological history rather than recent dispersal, and Mormyridae is the African branch, by far the most species-rich family in the order. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) lists Myomyrus macrodon as the currently accepted name, with Boulenger as sole author.
Genus Myomyrus was likewise erected by Boulenger, and it is one of several mormyrid genera built on the -myrus root of Mormyrus, the family's type genus, itself borrowed from mormyros, an ancient Greek name for an unrelated marine fish later repurposed for these African electric fishes. The species name macrodon comes from the Greek makros ("large") and odous/odon ("tooth"), describing the fish's conspicuous teeth relative to its relatives — a useful diagnostic feature, since like many mormyrids it is otherwise difficult to tell apart from close relatives by external anatomy alone, without comparing electric-organ discharges.
Morphology
Like other mormyrids, Myomyrus macrodon has an elongated, laterally compressed body, a small mouth, and no adipose fin. FishBase records a maximum length of about 9.4 in total length for the species, a modest size within the family, well short of the largest Mormyrus species that approach a metre, though still a fish that needs real swimming room rather than a small tank.
The single most important structure in the animal is one most aquarists never see directly: a specialised electric organ in the caudal peduncle, built from modified muscle cells called electrocytes, which fires a weak, species-specific pulse-type electric organ discharge (EOD). Paired with electroreceptors spread across the skin, the EOD lets the fish build a picture of its surroundings in dark or turbid water and lets individuals recognise their own species and read the identity and status of other mormyrids nearby. Supporting this sense is a brain that is large relative to body size, with an enlarged cerebellum devoted to processing the constant stream of electrosensory information — mormyrids are regularly cited among fishes with the highest brain-to-body mass ratios. Because many mormyrid species look alike, ichthyologists increasingly rely on the EOD waveform itself, not just external anatomy, to distinguish close relatives.
Habitat
Myomyrus macrodon is a Congo Basin endemic. FishBase lists its range across the Democratic Republic of the Congo and Zambia, and a survey of the Itimbiri, Aruwimi and Lindi-Tshopo rivers — tributary systems in the northern DRC — confirmed the species within that river network. The Congo Basin as a whole holds the highest diversity of mormyrids of any African drainage, a product of its size, age and the complexity of its tributary network, and M. macrodon is one contributor to that richness rather than a wide-ranging generalist.
FishBase classifies the species as demersal and tropical freshwater, consistent with the rest of the family: it lives near the bottom of river channels rather than in open water. Congo Basin rivers of this kind are typically warm and often stained brown with dissolved tannins from surrounding forest, conditions under which vision is limited and an electric sense is at an advantage, but precise temperature and water-chemistry data specific to this species' home rivers were not available in the sources used for this account, so any figures given here should be treated as general Congo Basin guidance rather than measurements taken at a known locality.
Feeding
Specific dietary studies of Myomyrus macrodon were not found for this account, but the feeding ecology of Mormyridae as a family is well characterised, and there is no reason to expect this species departs from it. Mormyrids are largely nocturnal, bottom-foraging invertivores: they use the electric sense, not eyesight, to detect prey buried in sand or hidden among leaf litter and root tangles, then take it with a quick suck of the small mouth. Typical prey across the family includes insect larvae (particularly chironomid "bloodworms"), small crustaceans and other soft-bodied invertebrates.
In captive mormyrids generally, keepers replicate this with live and frozen foods offered after the lights go down — mosquito larvae, bloodworm, Daphnia and Tubifex are the standard menu — since these fish are reluctant to compete for food in bright light or against faster, sighted tankmates. Dry foods are rarely taken with any enthusiasm, and a fish that will not adapt to prepared food should not be assumed to be thriving just because it is still swimming.
Mating
Courtship and mate recognition in Mormyridae runs largely through the electric channel rather than visual display. The EOD carries information about species and individual identity, and in many mormyrids the discharge pattern shifts during courtship interactions, giving the fish a private communication channel other river residents cannot read. Beyond that family-wide pattern, nothing specific to the courtship behaviour of Myomyrus macrodon has been documented in the sources reviewed for this account.
Like other Congo Basin fish, mormyrids are generally believed to spawn seasonally, timed to seasonal rains and the resulting rise in river and floodplain water, which opens newly flooded vegetation as feeding ground and, presumably, spawning habitat. Data on the precise cues, courtship sequence or mate choice in M. macrodon specifically are sparse to absent, which is typical for the genus as a whole.
Breeding
Mormyrids as a family are essentially unbred in the home aquarium, and Myomyrus macrodon is no exception: there is no established captive-breeding protocol for the species, and it is not bred commercially or by hobbyists in any documented, repeatable way. What little is known of mormyrid reproduction in the wild comes from scattered field observations rather than controlled study — spawning is thought to be seasonal and flood-triggered, and some mormyrid species are believed to scatter or deposit eggs among flooded vegetation with some form of guarding behaviour afterward, but the details vary by species and remain poorly resolved even for the better-studied ones.
For M. macrodon specifically, no breeding account exists in the literature reviewed for this profile. Any specimen offered for sale is wild-caught, and prospective keepers should not expect to reproduce this species in a home tank; it belongs in the same essentially-unbred category as nearly every other mormyrid in the trade.
In the aquarium
Myomyrus macrodon is rarely if ever seen in the aquarium trade. It is a plain-looking Congo Basin river endemic overshadowed commercially by showier mormyrids such as the elephantnose, Gnathonemus petersii, and most of what follows is extrapolated from general mormyrid husbandry rather than species-specific experience. Any specimen that does turn up should be treated as a wild-caught fish that has already survived a difficult import chain and given time and quiet conditions to settle before it is expected to feed normally.
General mormyrid care applies: soft, dim water over a fine sand substrate — these fish probe the bottom with the snout and can abrade themselves on coarse gravel — plenty of cover such as driftwood, roots and broad-leaved plants, and subdued lighting, since mormyrids become withdrawn and stop feeding under bright light. A tank of at least 39.4 in in length is a sensible minimum for a fish that can reach 9.4 in. Mormyrids are frequently intolerant of their own kind and sometimes of other mormyrids, so a single specimen or a genuinely large group to disperse aggression are safer choices than a pair or trio; tankmates should be calm, non-competitive fish that will not out-hustle a nocturnal forager for food.
The single most important care note is medication sensitivity: mormyrids are notably intolerant of copper-based treatments and of formalin, both of which can be lethal, so any medication should be dosed conservatively and used only when clearly necessary. Water quality matters more than usual too — the electric organ discharge frequency of mormyrids is known to shift under pollution stress, a useful early warning sign of declining conditions.
Conservation
The IUCN Red List category cited for Myomyrus macrodon, via FishBase's summary of the assessment, is Least Concern, assessed 16 February 2009. That reflects a species with a reasonably wide range across Congo Basin tributary systems in the Democratic Republic of the Congo and Zambia rather than a narrow single-river endemic, and no documented population decline or major point threat.
That assessment is now over fifteen years old, and the Congo Basin as a whole faces mounting pressure from deforestation, artisanal and industrial mining, and proposed hydropower development in some tributary systems — pressures that affect Congo Basin fish communities broadly even where no species-specific reassessment has been carried out. Myomyrus macrodon is not currently flagged as threatened, but its Least Concern status is best read as "no evidence of decline documented" rather than as a fish under active, ongoing monitoring.