Elephant nose fish (lat. Gnathonemus petersii) is a freshwater fish species of Mormyridae family. The fish got its specific name in honor of German zoologist Wilhelm Peters (1815—1883). It looks quite unusual due to construction of its mouth that is a trunk-like and resembles elephant’s nose. This fish species requires special tank conditions and therefore it’s not recommended for beginner aquarists.
Habitat in the wild
The elephant nose fish is widespread in central and western part of African continent (Niger River, Ogun River and Chari River). It dwells in near bottom layer of muddy waters, prefers areas with slow water flow and thickly growing plants.
This is a bottom-lying fish that lives near bottom and looks for food by means of the long protrusion on its head. Besides, the elephant nose fish has developed an unusual quality – this is a weak electric field by means of which it performs spatial navigation, looks for food and communicates with its relatives.
The elephant nose fish feeds on insects and various small spineless species, which it can find in the bottom substrate.
|Scientific Name||Gnathonemus petersii|
|Common Names||Peters’s elephantnose fish; elephant nose fish; nose fish; dolphin nose fish|
|Range and habitat||Africa|
|Size||25 cm (9.8 in)|
|Ease of keeping||Difficult|
|Minimum tank size||300 liters (66 gallons)|
|Temperature||26–28 °C (79–82 °F)|
|pH||6.8 – 7.2|
|Water hardness||5-15 dGH|
In the wild elephant nose fish can grow up to 3o cm long, but in captivity its size as a rule doesn’t exceed 25 cm (9.8 in). Its lifespan in a tank is about 10 years.
The body is elongated and flattened from sides. It doesn’t have abdominal fins, the pectoral ones are rear, dorsal and anal fins are symmetrically located almost near the forked caudal fin base. The place where the body joins with the tail fin is very thin.
The body coloring is dark-brown almost black and at certain lighting it can opalize with violet tint. Two light colored roundish arc-shaped lines connect dorsal and anal fins from both sides.
The elephant nose fish distinctive feature is its ‘mouth’ namely its ‘trunk-like’ underlip, that makes it look like an elephant. This organ has lots of nerve endings and can produce low electrical pulses that allow the fish to navigate in muddy water, find food, a partner and identify hazards.
Difficulties in keeping
The elephant nose fish is demanding in terms of keeping, since fish requires ideal water parameters and it is very sensitive to medicines and toxic substances content in the water. Besides, this is a timid fish, it becomes active in the evening and at night and it is demanding in terms of feeding.
When there are many fish species in a school they demonstrate more friendly and peaceful behavior provided with enough space and sufficient number of shelters in a tank.
Care and keeping in the tank
The elephant nose fish requires a roomy tank – from 300 liters (66 gallons) capacity. The larger the fish school is, the larger should be the tank.
It’s good to keep this fish in a school of at least 3-4 species, but it’s even better when there are 5-7 ones. In a large school the elephant nose fish feels more comfortable and tends to demonstrate aggression more seldom. Therefore, optimal number of the species in a school is 4-7, if you keep just two of them, then the alpha male may behave very aggressive continuing until death of the weaker fish.
The elephant nose fish needs shelters, at that their number should be equal or exceed the number of species in a tank. Smooth stones, snags and tank plants that can live at the conditions of low lighting, such as anubias, fern of Microsorium kind – all these can serve as shelters.
Sand or other soft substrate will do as the bottom one, otherwise the elephant nose fish may damage its trunk-like underlip which will make feeding it difficult. The tank should have a lid, since the fish may jump out of the water.
In the wild this fish is active at night or in the evening, therefore it is important that the tank light is dim – the fish can’t stand bright light. Semidarkness, lots of shelters where the fish will stay during the day and come out sometimes to feed or to swim – there are all the conditions the fish requires.
The elephant nose fish is very sensitive to water composition change and because of this it’s not recommended for inexperienced aquarists as well as it can’t be kept in tanks where tank water parameters aren’t stable. Like other ganoid species, elephant nose fish is sensitive to most tank chemicals including salt.
The elephant nose fish is also sensitive to ammonia and nitrates content in the tank water considering that these tend to accumulate in the bottom substrate and the fish is a near bottom dweller.
Using powerful canister filter is a must as well as weekly water renew and cleaning the bottom substrate, you should also control ammonia and nitrates content in the water.
Tank water temperature should be 26–28 °C (79–82 °F), dGH 5-15 °, pH 6.8 – 7.2. Filtration and aeration are required, again the elephant nose fish is very sensitive to the water quality, one third of which you have to renew every week.
Elephant nose fish feeds mainly on insects and their larvae which it can find on the bottom. That’s why you should feed it first of all with bloodworm and tubifex. Some species can eat frozen and artificial food as well as well, but still you should give preference to live food.
You have to take into account the fact that elephant nose fish eats slowly, therefore don’t keep it together with fast and omnivorous species, because they can eat its food.
The fact, that the fish is trustful is particularly noteworthy, because in time you may train it to eat from your hands. One of the main criteria when feeding the elephant nose fish is that this is a nocturnal species and that’s why you should feed it either after you turn off the lights or shortly before this.
This is calm and peaceful, but territory depended species. It is compatible with almost any tropical species, however if there isn’t enough space intraspecific fights in the tank are inevitable. The elephant nose fish shouldn’t be kept with very active or aggressive tank mates, since it won’t be able to compete with them during the feeding process.
Gender differences: male vs female
It is unknown how to tell between the male and female. They have quite little pronounced dimorphism. It is considered that elephant nose fish females are larger and they have more rounded abdomen.
For now there had been no recorded successful cases of breeding in a tank. Therefore this fish isn’t bred in captivity and all the species you see on sale were caught in the wild.