Although the South American knifefish called an electric eel, is now the archetypal electric fish in the western mind, the Egyptians and Greeks long before knew of electric catfishes in Africa. These fish had such a cultural impact in antiquity, that a renowned pharaoh took the name Barmer, or 'electric catfish', as his throne name. Ichthyologists and aquarists also have an interest in the electric or malapterurid catfishes. Unfortunately they are taxonomically confusing to scientists, and related confusions might account for contradictions and falsehoods in the care related information, that is produced for fishkeepers.
Although many people assume any electric catfish belongs to the type species, it seems that most of them (at least recent imports) are Malapterurus beninensis, the Benin electric catfish, imported from Nigeria. This is a much smaller animal than the otherwise similar type species, M. electricus, which is present in the Nile and amazed the ancients with its then inexplicable powers. M. beninensis is a Guineo-Congolian species from the rivers, streams, lakes, marshes and swamps in the tropical lowlands of western and central Africa, distributed from the lower Volta to Chiloango systems. This species grows to around 22 centimeters, or 9 inches long.
Despite their obvious specializations including their impressive electrical organ, the Afrotropical malapterurids have remained, in many ways, an anatomically protomorohic group. Genetic analyses have not really cast much light on their more precise relationships to other catfish groups. Anatomically they resemble clades such as the silurids and the auchenoglanids. Though there are now recognised to be many more species of malapterurid than was once thought to be the case, they do not have much disparity of form and function, as is seen in some of the other catfish clades. That is to say that they have not been changed much by further evolution, being very efficient at their lifestyles as electric predators.
Like other species in Malapterurus, M. beninensis is a nocturnal and passive carnivore, that needs wood and maybe rocks to hide among in the aquarium. Fishes of this genus are averse to strong water flow, though they have a reputation, as a group, for being adaptable and indifferent to matters of harness and pH. In the wild, M. beninensis usually inhabits waters with a pH between 6.5 and 7; on a seasonal basis, it may ascend as high as close to 8, or drop closer to 6 at some localities. But it is basically a fish of circumneutral waters, leaning toward soft and acidic conditions. The temperature of the water is naturally similar to that of our tropical tanks, for example, from 26 to 29 degrees centigrade is appropriate.
Although M. beninensis has a potentially lethal shock, it is not inclined to use it except defensively or in search of food. As long as other fish will not bother them, and are also too large to be hunted by them as food, they are tolerated by these slow swimming catfishes. which are strictly bottom dwellers. If in doubt accommodate them only with species that will not compete with them for spatial use, for example, not with other demersal or benthopelagic fishes. Or those likely to shelter in the same location. Their own diet is meaty chunks, either defrosted or fresh pieces from the fishmongers. Some individuals will take to eating proprietary sinking foods for carnivorous fish.
There are in fact a few species of Malapterurus but the basic care is the same, though they vary in such details as their mature sizes. Not all come from the same African waters, and they may have different needs and preferences. The mighty M. electricus for example, grows to over 120 centimeters, or 48 inches, and based upon wild habitats, should prefer harder and more alkaline water, perhaps up to a pH of about 8. It isn't always clear which species has been imported, even to the eye of an ichthyologist, but their locations of origin, if they are known, ought to at least be a clue to their best care.