Elephantfish

Adults can reach a length of approximately 22 cm. Distinguishing males from females is quite difficult, as sexual dimorphism is very weakly expressed. A unique feature of this species is its "trunk" — in fact, an elongated lower jaw, used as a probe to search for food in silty substrate. The body coloration is charcoal black, adorned with two light vertical stripes located closer to the caudal part, between the dorsal and anal fins. Gnathonemus petersii is noted to be primarily active at night. In low light conditions, for orientation and foraging, it relies not on vision but on a special electrogenic organ located in the tail, which constantly generates weak electric fields. Electroreceptors on the head allow it to detect even the slightest changes in this field, helping the fish to "see" its surroundings.

This species originates from the African continent. Despite the trade name “Nile elephantfish”, the species does not occur in the Nile at all. Its range covers the rivers of West and Central Africa: from the lower Niger and the Ogun to the Congo basin and the upper Chari; it is known from Mali, Benin, Niger, Nigeria, Chad, the Central African Republic, Cameroon, both Congos and Zambia. They most often inhabit murky, slow-moving waters, preferring bottom layers with abundant aquatic vegetation.

Despite its calm nature, this species exhibits territorial behavior. The Elephantfish is not prone to cohabitation with its conspecifics; stronger individuals can even lead to the death of weaker ones. Nevertheless, they are well compatible with other peaceful but not overly active fish. Potential tank mates include Anabantids, Synodontis, Congo Tetras, and Butterflyfish, as well as a number of African river cichlids.

For comfortable living, a single specimen requires an aquarium of at least 250 liters. Key conditions for successful keeping of the Nile Elephantfish include subdued lighting and a soft substrate type. Aquarium design can include driftwood, smooth stones, and shade-tolerant plants such as Anubias, Vallisneria, as well as various mosses and ferns. Particular attention should be paid to the choice of substrate: a hard or sharp substrate can damage the fish's sensitive "trunk," making feeding difficult. Maintaining stable water parameters is also paramount. It is advisable to install a high-performance filtration system, but when choosing it, one should consider that these fish tolerate strong water currents poorly. Therefore, preference should be given to models that do not create excessive water movement. As for regular care, it is standard: weekly partial water changes are necessary, and organic waste should be removed regularly.

Regarding diet, this species is not particularly demanding. The Nile Elephantfish readily accepts various types of food: dry, frozen, or live. An important condition is that the food must be sinking, for example, granules or flakes combined with bloodworms.

Breeding these fish in home aquariums has not yet been successful. One of the factors preventing spawning is the fish's use of electrical impulses to recognize individuals of their own species, including for sex identification. In captivity, sensitivity to these impulses can decrease, which hinders them from finding a partner.

Health problems in fish are most often associated with unfavorable keeping conditions. Poor water quality, an unsuitable diet, or mechanical damage can cause various infectious diseases. In a well-balanced aquarium environment, health problems generally do not arise.

When choosing an Elephantfish in a store, pay attention to the condition of its skin, as this species lacks scales, making it extremely vulnerable to infections and mechanical damage. A healthy individual should be active (in the evening), without visible ulcers, film, spots, or damage in the area of the mouth-proboscis, which is a key feeding tool. Avoid purchasing fish that appear emaciated, have a sunken belly, or show signs of apathy, constantly hiding even in subdued light. It is important to consider that these fish are very sensitive to water quality and stress during transportation. Before purchasing, ask the seller how long the fish has been in the store and what it is fed, as some individuals may refuse unfamiliar food. Refuse to purchase if aggressive tank mates are kept with Elephantfish or if signs of death of other individuals are observed in the same system, as Gnathonemus are extremely susceptible to diseases and tolerate treatment with common medications poorly.