mormyrids

Mormyrids, or elephantfishes, are a diverse family of freshwater fishes in the order Osteoglossiformes, native to sub-Saharan Africa. The family includes hundreds of species across numerous genera and exhibits a range of forms, with many species possessing a long rostrum.

A defining trait is their weak electric sense. Mormyrids have a specialized electric organ, usually along the tail, that emits electric organ discharges (EODs). Electroreceptors distributed over the skin detect distortions in the surrounding field, enabling electrolocation and electrocommunication. EODs are species-specific and used in navigation, social interactions and mate recognition. The brains of mormyrids are relatively large and show specialization for processing electric signals.

Ecology and behavior: They inhabit rivers, lakes and floodplains in freshwater habitats, often in murky water. They are primarily nocturnal and benthic or mid-water feeders, feeding on small invertebrates such as insect larvae and crustaceans, and, in some species, detritus.

Reproduction and size: Reproduction is sexual, with eggs laid by females and, in several species, courtship displays described. Adult sizes range from about 10 to 40 cm, with some species larger.

Conservation: Habitat degradation, pollution and overfishing threaten some species. They are also kept in the aquarium trade, valued for their distinctive appearance and ecologically interesting electric sense.