Elephantnose Fish, lat. Gnathonemus petersii- Gnathonemus petersii distribution
Family: Mormyridae;
Genus: Gnathonemus;
Species and synonyms: Elephantnose Fish (Gnathonemus petersii, Elephant Nose, Elephant Fish, Long-nosed Elephant Fish, Peter's Elephantnose).
GBIF:
Elephantnose Fish (lat. Gnathonemus petersii) is a species of ray-finned fish from the order Mormyriformes, family Mormyridae, genus Gnathonemus. One of the most unusual and recognizable freshwater fish due to its long trunk-like snout.
Distribution. The natural range of the Elephantnose Fish covers rivers and lakes of West and Central Africa, including the Niger, Congo and Ogowe river basins. The fish prefer slow-moving or stagnant waters with sandy or muddy bottoms, often found in backwaters and floodplain lakes with dense vegetation.
Care requirements. The Elephantnose Fish grows up to 20–25 cm in the aquarium and up to 35 cm in the wild. To keep a group (3–5 specimens), an aquarium of at least 200 liters with a length of 120 cm is recommended. A tightly fitting lid is essential, as the fish may jump out. Optimal water parameters: temperature 24–28°C, hardness 5–15 dGH, pH 6.0–7.5. Powerful filtration with moderate flow, good aeration and weekly water changes of 20–25% are necessary. Sandy or fine gravel substrate, driftwood, stones and shelters are placed at the bottom. Plants should have tough leaves.
Elephantnose Fish are predators, feeding on small invertebrates, insect larvae and worms in the wild, which they find using their sensitive snout. In the aquarium, their diet should consist of live and frozen foods (bloodworms, tubifex, brine shrimp, daphnia, glassworms, worms). They can also be trained to accept high-quality sinking pellets. It is important to provide protein-rich food. Feed should be 1–2 times a day in the evening, as the fish are crepuscular.
In the aquarium, Elephantnose Fish are active in the lower and middle water layers. They are peaceful towards fish of similar size, but may eat small fish. Recommended tankmates include large characins, cichlids, catfish, other mormyrids. It is not recommended to keep them with small fish that will be perceived as food.
Intelligence and unique abilities. The Elephantnose Fish is considered one of the most intelligent fish on the planet. In terms of relative brain-to-body mass, they surpass humans: in Gnathonemus, the brain makes up to 3.1% of body weight, while in humans it is about 2–2.5%. Moreover, the brain of the Elephantnose Fish consumes up to 60% of the absorbed oxygen, which is a record among animals.
This fish navigates in murky water using weak electrical impulses generated by a specialized organ in its tail. Scientists have proven that Elephantnose Fish are capable of "collective perception": in groups, they exchange electrical signals, allowing them to jointly "see" objects at a distance three times greater than individually. Their "language" consists of streams of electrical impulses, with which they regulate all aspects of life: foraging, courtship, aggression and cooperation.
Studies show that bolder individuals learn faster, and in the presence of conspecifics, fish can use their electrical signals to save energy when searching for food — a phenomenon called "freeloading". This is why in nature and in the aquarium, it is recommended to keep these fish in groups: solitary individuals die faster from stress.
Breeding in home aquariums is extremely difficult and rarely occurs in hobby aquariums. Elephantnose Fish are egg-laying, but spawning requires special conditions and hormonal stimulation. Sexual differences are weakly expressed. In the aquarium hobby, most fish come from the wild or specialized farms.
The Elephantnose Fish gets its name from the long extension on its lower jaw, which resembles an elephant's trunk. This organ is used for finding food and spatial orientation, as the fish has poor eyesight and navigates using electrical impulses. The body coloration is dark brown or black with two white stripes on the sides. Life expectancy is 8–12 years.