Bonytongues · Elephantnoses & mormyrids

Campylomormyrus bredoi

(Poll, 1945)

IUCNVULNERABLE · 2009
CARESNOT LISTED
Scientific size14.6 in37 cm total length
Temperature75–82 °F24–28 °C
pH6–7.5neutral
Depthnot recorded
DietBenthic invertebrate feeder — insect larvae, worms and other soft-substrate prey located mostly by electrolocation after dark; in the aquarium takes live or frozen bloodworm and brine shrimp, best offered once lights are down
BreedingSeasonal spawner; breeding poorly known and rarely achieved in captivity
Sexual dimorphismMinimalNo reliable external sexual dimorphism reported; sex is difficult to determine visually in this genus
PhotographsSee photosGoogle Images →

Campylomormyrus bredoi is a weakly electric mormyrid from the upper Congo basin, a member of one of the oldest surviving branches of the bony fishes, the bonytongues (order Osteoglossiformes). Like its relatives in the family Mormyridae it reads its dark, sediment-laden world through an electric organ in the tail, firing a pulse-type discharge to electrolocate food and to recognise its own kind — a sense system built around one of the largest brain-to-body ratios of any fish. Confined to Lake Mweru and the lower Luapula River on the Congo–Zambia border, it reaches a modest 37 cm total length and carries the elongated, downward-curving snout that gives the genus Campylomormyrus its name. The IUCN lists it as Vulnerable, worn down by trawl-net fishing pressure on the very lake it is named from.

What's in the name

Campylomormyrus bredoikam-pih-loh-MOR-mih-rus bred-OH-eye

Campylomormyrus
  • kampylosGreekcurved, bent — describing the genus's downward-arcing snout
  • MormyrusLatinised Greekthe type genus of the family, an old name for the Nile mormyrid fishes
bredoi
  • Brédoeponymhonours Hans Joseph Anna Erich Richard Brédo (1903–1991), a Belgian government entomologist who collected in the Congo during the 1930s

Taxonomy & naming

Campylomormyrus bredoi was described by the Belgian ichthyologist Max Poll in 1945. It sits in the family Mormyridae — the elephantnoses and mormyrids — within the order Osteoglossiformes, the bonytongue fishes, a lineage named for a toothed bone on the floor of the mouth that bites against toothed plates on the roof and that traces back to some of the earliest branch points in the teleost family tree. Poll originally placed the species in the older, broader genus Mormyrus before it was reassigned to Campylomormyrus, the group of long, downward-curved-snout mormyrids now recognised as a distinct genus within the family.

The species epithet honours Hans Joseph Anna Erich Richard Brédo (1903–1991), a Belgian government entomologist who collected extensively in the Congo during the 1930s; bredoi is a straightforward Latin genitive dedication, "of Brédo". No common name is well established for this species in the aquarium trade — it is generally sold and discussed under its scientific name, or simply lumped in with the broader run of "elephantnose" mormyrids that reach hobbyists sporadically from Central Africa.

Morphology

The defining feature of the genus, and the source of its name (Greek kampylos, "curved", + Mormyrus), is the long, tube-like snout that arcs downward toward the substrate. In Campylomormyrus bredoi this curved snout houses the mouth at its tip and, together with the skin over much of the body, is densely packed with electroreceptors used to read the fish's own electric field as it probes for food in the dark. FishBase reports a maximum size of about 14.6 in total length, a mid-sized mormyrid by the standards of the genus — some Campylomormyrus species run smaller, others considerably larger.

Like other mormyrids, C. bredoi carries a specialised electric organ near the base of the tail that generates a weak, species-specific pulse-type electric-organ discharge (EOD). This sense is backed by an outsized cerebellum relative to body size — mormyrids are frequently cited as having among the highest brain-to-body mass ratios of any fish, the neural cost of processing a constant stream of electrolocation and communication signals. Body colour is typically a dark grey-brown to blackish, without the bold patterning seen in some other African fish groups; many mormyrids, including species in this genus, are reliably told apart only by comparing their individual EOD waveform rather than by external appearance alone.

Habitat

Campylomormyrus bredoi is known from Lake Mweru and the lower Luapula River, in the upper Congo basin on the border of the Democratic Republic of the Congo and Zambia — the type locality given for the species is Pweto, on Lake Mweru. It is a demersal, tropical freshwater fish, living and feeding near the bottom rather than in open water.

As with mormyrids generally, its native water is warm, typically soft and only mildly mineralised, and often turbid or dimly lit by suspended sediment and dissolved tannins — precisely the low-visibility conditions that make an electric sense so useful. Specific published temperature and pH figures for the Lake Mweru/Luapula population are not available; aquarists keeping the species work from the general Congo-basin mormyrid range of roughly 75–82 °F in soft, slightly acidic to near-neutral water rather than site-specific data.

Feeding

In the wild, Campylomormyrus bredoi forages over soft bottom sediment for small aquatic invertebrates — insect larvae, worms and other benthic prey — locating them mostly by electrolocation rather than by sight, since it is most active around dusk and after dark. The long, curved snout functions as a probe, sweeping close to the substrate within the range of its own electric field.

In the aquarium it is not a fussy eater once settled, but it is a live-food and frozen-food specialist rather than a flake or pellet fish: bloodworm and brine shrimp are the reported staples, offered after the lights go down to suit its nocturnal foraging habit. Because it is a slow, deliberate feeder that relies on chemical and electrical cues near the substrate, it can lose out to fast, sighted tankmates competing for the same food and often does best fed directly once other fish have settled.

Mating

Courtship and species recognition in mormyrids run through the electric-organ discharge: each species produces a distinctive EOD waveform, and individuals are thought to use small variations in that pulse to assess sex, species identity, and readiness to spawn in the crowded acoustic-like "electric" environment of a Congo basin river or lake. Beyond that broad pattern, the courtship behaviour of Campylomormyrus bredoi specifically has not been documented in the literature available for this account.

Mormyrids as a group are seasonal, flood-triggered spawners, timing reproduction to the rise of water levels that opens up flooded marginal habitat. The fine detail of pairing, egg-laying and site selection in this species is essentially unknown — a fair reflection of how little of mormyrid reproductive biology has been observed in the wild at all, let alone for a single-basin species like C. bredoi.

Breeding

Campylomormyrus bredoi is essentially not bred in captivity, and mormyrid reproduction generally remains poorly understood even in the wild. What little is known points to seasonal, flood-triggered spawning tied to the rains and rising water in the Congo basin, with the species-specific EOD likely playing a courtship role; some mormyrids are thought to scatter or guard eggs among flooded vegetation, but the details for this species are not documented.

Given the near-total absence of captive breeding reports, aquarists should not expect to reproduce this fish, and any claim of a reliable breeding method for C. bredoi should be treated with scepticism. The species reaches hobbyists as wild-collected stock, infrequently exported from the Congo basin, rather than through any established captive-breeding programme.

In the aquarium

Campylomormyrus bredoi is an infrequently exported, specialist fish rather than a beginner's choice. It wants a dimly lit tank with soft substrate, ample hiding places (caves, driftwood, dense planting or floating cover) and stable, clean water with minimal turbidity — mormyrids are notably intolerant of poor or fluctuating water quality, and their electroreceptive skin makes them more sensitive than most fish to medications, so copper-based treatments and other harsh chemicals should be avoided or dosed with particular caution.

Diet should lean on live or frozen invertebrates — bloodworm and brine shrimp are the reported staples — offered after dark to match its nocturnal foraging. Mormyrids, including species in this genus, can be intolerant of their own kind and of similarly shaped tankmates, so stocking needs care: a single specimen, or a genuinely large, well-furnished tank if attempting a group, with places for subordinate fish to retreat out of sight of dominant individuals. At a maximum of roughly 14.6 in total length this is a mid-sized commitment rather than a giant, but it is still a long-lived, specialist fish that repays a quiet, softly lit, well-established aquarium rather than a busy community tank.

Conservation

The IUCN Red List assesses Campylomormyrus bredoi as Vulnerable (VU), an assessment made on 16 February 2009 under criterion B1ab(v) — a small range combined with a continuing decline. The stated threat is overfishing with trawl nets in Lake Mweru and the Luapula River, the whole of the species' known range.

Because C. bredoi is confined to a single lake-and-river system rather than distributed across the wider Congo basin, it has little buffer against sustained fishing pressure in that one location. The aquarium trade is a minor factor by comparison — the species is popular in principle among mormyrid enthusiasts but only infrequently exported — with commercial fisheries on Lake Mweru the driver behind its threatened status.

Sources

  1. FishBase — Campylomormyrus bredoi (Poll, 1945)
  2. IUCN Red List — Campylomormyrus bredoi
  3. Practical Fishkeeping — The definitive guide to elephantnoses
  4. Wikidata — Campylomormyrus bredoi (taxonomy and etymology records)

Last reviewed 2026-07-17.

How to cite

Aquarist Atlas (2026). Campylomormyrus bredoi. Aquarist Atlas.https://www.aquaristatlas.com/bonytongues/campylomormyrus-bredoi/

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