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The Elephantnose Fish: The Stranger Thing

  • Scientific name: Gnathonemus petersii
  • Common name: Elephant fish, elephantnose fish
  • Aquarium size: 100 to 200 liters
  • Temperament: Calm
  • Temperature: 75.2ºF to 82.4ºF
  • pH: 6 to 6.5
  • Diet: Carnivore
  • Length: 9 inch


The elephantnose fish one of the best known representatives of the Mormiridae family (Mormyridae).

The entire family of these fish is known as “elephant” fish, due to a fleshy protrusion that they have under their mouth, in what we could call the “chin” of the fish, which resembles the trunk of the famous mammal.

It is a peaceful fish with other species, sociable and can even be somewhat shy, but it is territorial with other fish of the same species, even dominant with other weaker specimens.

Although at first glance the most striking thing about this species is its morphology, it is a fish that hides many curious characteristics, such as its great intelligence, which makes it capable of learning tasks.


Its size in the aquarium rarely exceeds 9 inch, although in the wild it can measure about 13.75 inch long.

As I have commented, the most striking thing about their morphology is the bulge they have under their mouths, like a trunk.

This protuberance, called a schnauzenorgan, is used to search the bottom of rivers and find their prey. It has tactile receptors and it is believed that even taste.

It is an elongated, laterally compressed fish, with a forked caudal fin on a fleshy stalk.

Dorsal and anal fins set far back, are equal in size, highly developed and appear almost symmetrical.

Another peculiarity of this curious fish is that it does not have scales, which is why it is very sensitive to certain chemical substances in the aquarium, such as medicines, salt, and even water quality.

Its coloration is brownish to a very dark anthracite gray, almost black. It has white bands in the shape of parentheses on the back of the body, at the level of the caudal and anal fins. The rear bands are somewhat smaller and the front bands are larger and thicker.

The fins have a whitish edging.

The electrical impulses of the elephant fish

The elephantnose fish produces small electrical impulses, which create an electrical field around the fish. The electricity is generated thanks to a muscular tissue that it has in the caudal peduncle.

These impulses help it avoid obstacles in the dark, pursue live prey in cloudy water or at night, as well as to recognize other individuals of its species, find a mate and orient itself.

If you haven’t figured it out yet, his vision is rather poor.

Sexual dimorphism

There are no obvious differences between male and female elephant fish, although some aquarists suggest that it is possible to identify them by differences in the anal fin, although this is not proven.

Differences can be found between the electrical fields produced by females and males, but it is evident that it is impossible to detect it by eye examination.

Distribution and habitat

They come from Africa, where they can be found in Mali, Benin, Nigeria, Chad, Cameroon, the Republic of the Congo and Zambia.

They like rivers with abundant vegetation and slow waters, with muddy bottoms and low visibility.

Aquarium conditions

If we want to recreate its original habitat, we need an aquarium with a profusion of both bottom and floating plants, which serve as a filter for the light in the aquarium, which should be rather dim.

We must provide them with places to hide, with aquarium rocks, logs and roots.

The bottom of the aquarium should be sandy, since they like to look for their prey in the sand. They rummage and dig, if we put an aquarium substrate with stones, it will hurt them and if they can’t move the bottom, they will get frustrated.

The minimum size of the aquarium should be around 26.41 gallons to 52.82 gallons (better large) for one specimen. If we are going to have more than one specimen, we should go to 79.25 gallons or 105.66 gallons.

Water quality

They are fish that need optimal water quality, are very sensitive when the nitrate concentration is high, causing them to discharge a greater number of discharges, and can contract fungal diseases. Amoxicillin for fish

pH between 6 and 6.5

Hardness between 5º and 10º GH


One of the great challenges in keeping the elephant fish in the aquarium is its diet, which is highly specialized. In nature they eat mainly live prey, small crustaceans, invertebrates and enchytreids (worms).

In the aquarium and once adapted, they will take almost any type of dry or live food: tubifex, daphnia, scales, granules and all kinds of freeze-dried food.

Their habits are nocturnal, although sometimes they can be active during the day. This means that we must feed them at the end of the day, when they are most active.

As I have mentioned before, they are quite blind, their way of orienting themselves is by the electrical impulses they generate.

This means that they are very bad at competing for food. In a community aquarium, it will be necessary to be very careful that it receives the correct food, and that it does not have to compete with other fish.

Behavior and compatibility

They tend to be more active at night, when they have no problem finding their way around. They are quite calm and rather shy. They have no problem sharing space with other species. However, with other congeners it can become territorial and aggressive. In a group there is usually a dominant male, who tends to harass the weaker specimens. They like to swim at the bottom of the tank, like cobitids.


So far, reproduction in the aquarium has been impossible, although it is comforting to know that their life expectancy is about 5 years.

According to some scientific studies, it may be that the fact that fish of the same species recognize each other through electrical impulses, and that they use this form of orientation to find a mate, may be diminished within the aquarium, and for this reason up to now it has been its reproduction