Elephantnose fish

The elephantnose fish is one of the most fascinating oddball species available to the aquarium hobby, thanks to its unique proboscis-like lower lip, weak electric field generation, and relatively large brain. It has a vast distribution across West and Central Africa, recorded from Mali to Zambia, inhabiting the dark, muddy beds and heavily-vegetated areas of slow-moving rivers. Adults reach approximately 22.5 cm (9 inches) in standard length.

This is a nocturnal, quiet but territorial species. It is peaceful towards other species but should not be kept with very active or aggressive fish, as it will be out-competed at feeding time. It also does not mix well with other mormyrids. If keeping more than one, purchase at least five specimens to disperse aggression within the group. A tank of at least 243 litres (120cm x 45cm x 45cm) is required, with dim lighting, plenty of cover, and critically, a soft sand substrate — the fish uses its trunk-like lip to probe for food in the substrate and sharp-edged gravel will damage its mouthparts.

Water conditions should be 23-28°C, pH 6.0-7.5, with moderate hardness. Diet is unfussy and includes a range of dried, frozen, and live foods, with worms being a particular favourite. Offer food after lights out if it is reluctant to feed under bright lighting. The elephantnose is very sensitive to deteriorating water conditions and to many aquarium medications (being scaleless). It uses a weak electric field for navigation, prey detection, and communication with conspecifics in total darkness — one of the most remarkable adaptations in the freshwater aquarium world.