Overview
The Double-nosed Elephantfish (Campylomormyrus rhynchophorus) is a specialized weakly electric freshwater fish endemic to the vast waterways of the Congo River basin. Characterized by an extraordinary down-curved tubular snout and chin extension, this bottom-dwelling mormyrid probes deep into thick river silt to detect hidden insect larvae. Equipped with an electric organ discharge (EOD) system and an exceptionally enlarged brain, it navigates turbid, zero-visibility waters using an active electrical sense.
Biology and Physical Characteristics
Campylomormyrus rhynchophorus possesses a compressed, elongated body clothed in small cycloid scales, displaying a muted iridescent silver-grey to chocolate-bronze coloration. Its defining anatomical feature is an exaggerated, downward-curving proboscis formed by elongated upper and lower jaws, tipped with a sensitive fleshy chin barbel packed with electroreceptors. In its tail peduncle, modified muscle cells form an electric organ that emits continuous weak electrical pulses, while specialized epidermal receptors detect distortions in the surrounding electric field.
Behavior and Ecology
Strictly nocturnal and benthic, the double-nosed elephantfish spends daytime hours sheltering among submerged roots, undercut banks, and rock crevices. As night falls, it glides across muddy riverbeds, sweeping its curved rostrum through sediment like a biological metal detector. When electroreceptive tuberous organs register the minute electrical potential or disturbance of an aquatic worm or chironomid larva, the fish extracts the prey with lightning suction. Mormyrids also use distinct electric pulse frequencies to communicate social status and territorial boundaries.
Conservation and Human Impact
Evaluated as Least Concern by the IUCN, Campylomormyrus rhynchophorus is abundant throughout the expansive Congo drainage. While subsistence artisanal fishers occasionally capture it in gillnets and fish traps, its deep-water habits and vast geographic distribution provide substantial protection. Potential future concerns include industrial mining runoff, sedimentation from deforestation, and planned hydroelectric dams that alter river flow regimes.
Interesting Factoid
Mormyrid fish like the double-nosed elephantfish possess a brain-to-body oxygen consumption ratio higher than any other vertebrate—including humans—due to the enormous cerebellum dedicated to processing electroreceptive data.
Last updated: October 2026