Peters' elephantnose fish
Encyclopedia
Peters' elephantnose fish (Gnathonemus petersii; syn. Gnathonemus brevicaudatus Pellegrin, 1919, Mormyrus petersii Günther, 1862) is an elephantfish in the genus Gnathonemus
. Other names in English include elephantnose fish, long-nosed elephant fish, and Ubangi mormyrid, after the Ubangi River
. As the Latin name petersii confirms it is named after someone called "Peters" (probably Wilhelm Peters
), although the apostrophe is often misplaced and the common name given as "Peter's elephantnose fish".
and Central Africa
, in particular the lower Niger River
basin, the Ogun River
basin and in the upper Chari River
. It prefers muddy, slowly moving rivers and pools with cover such as submerged branches. It is a dark brown to black in colour, laterally compressed (averaging 23–25 cm), with a rear dorsal fin and anal fin of the same length. Its caudal or tail fin is forked. It has two stripes on its lower pendicular. Its most striking feature, as its names suggest, is a trunk-like protrusion on the head. This is not actually a nose, but a sensitive extension of the mouth, that it uses for self-defense
, communication
, navigation
, and finding worms and insects to eat. This organ is covered in electroreceptors
, as is much of the rest of its body. The elephantnose fish has poor eyesight and uses a weak electric field
, which it generates by muscular contractions, to find food, to navigate in dark or turbid waters, and to find a mate. Peters' elephantnose fish live to about 6-10 years, but there are reports of them living even longer.
stores in the USA. In the aquarium (which should be at least 200 liters) it is timid, preferring a heavily planted environment with subdued lighting. Ideally, a pipe or hollow log should be provided. The substrate
should ideally be soft sand to allow the fish to sift through it with its delicate extended lip. It feeds on small worms (bloodworms) and aquatic invertebrates such as mosquito larvae, but in the aquarium will usually accept frozen or even flake food. How peaceful an elephantnose fish is can depend on the individual; some are quite aggressive with other species, while others are retiring. They may be kept in a community aquarium with peaceful species who share their water preferences. However, unless kept in an aquarium of over 400 liters, it is unwise to keep more than one elephantnose fish as they can be territorial. The conditions suggested to keep them in an aquarium are as follows: pH
of 6.8 to 7.2, water temperature 26 to 28 degrees Celsius, and water of medium hardness
. The substrate should always be something that does not irritate the sensitive snout of the fish.
The weak electrical impulses generated by this fish can be made audible by placing two electrodes in the fish tank, which are then hooked up to an audio amplifier or a piezoelectric earbud. The sonar-like clicks that this fish emits can sound like a squeaky door when the fish is excited.
Gnathonemus
Gnathonemus is a genus of elephantfish in the family Mormyridae.- Species :* Gnathonemus barbatus Poll, 1967* Gnathonemus echidnorhynchus Pellegrin, 1924...
. Other names in English include elephantnose fish, long-nosed elephant fish, and Ubangi mormyrid, after the Ubangi River
Ubangi River
The Ubangi River , also spelled Oubangui, is the largest right-bank tributary of the Congo River of Central Africa. It begins at the confluence of the Mbomou and Uele Rivers and flows west, then bends to the southwest and passes through Bangui, after which it flows south to the Congo at Liranga....
. As the Latin name petersii confirms it is named after someone called "Peters" (probably Wilhelm Peters
Wilhelm Peters
Wilhelm Karl Hartwich Peters was a German naturalist and explorer.He was assistant to Johannes Peter Müller and later curator of the Berlin Zoological Museum. In September 1842 he travelled to Mozambique via Angola. He returned to Berlin with an enormous collection of natural history specimens...
), although the apostrophe is often misplaced and the common name given as "Peter's elephantnose fish".
Description
Peters' elephantnose fish are native to the rivers of WestWest Africa
West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...
and Central Africa
Central Africa
Central Africa is a core region of the African continent which includes Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, and Rwanda....
, in particular the lower Niger River
Niger River
The Niger River is the principal river of western Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in southeastern Guinea...
basin, the Ogun River
Ogun River
The Ogun River is a waterway in Nigeria that discharges into the Lagos Lagoon.-Course and usage:The river rises in Oyo State near Shaki at coordinates and flow through Ogun State into Lagos State....
basin and in the upper Chari River
Chari River
The Chari or Shari River is a 949-kilometer-long river of central Africa. It flows from the Central African Republic through Chad into Lake Chad, following the Cameroon border from N'Djamena, where it joins the Logone River waters....
. It prefers muddy, slowly moving rivers and pools with cover such as submerged branches. It is a dark brown to black in colour, laterally compressed (averaging 23–25 cm), with a rear dorsal fin and anal fin of the same length. Its caudal or tail fin is forked. It has two stripes on its lower pendicular. Its most striking feature, as its names suggest, is a trunk-like protrusion on the head. This is not actually a nose, but a sensitive extension of the mouth, that it uses for self-defense
Self-defense
Self-defense, self-defence or private defense is a countermeasure that involves defending oneself, one's property or the well-being of another from physical harm. The use of the right of self-defense as a legal justification for the use of force in times of danger is available in many...
, communication
Communication
Communication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...
, navigation
Navigation
Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...
, and finding worms and insects to eat. This organ is covered in electroreceptors
Electroreception
Electroreception is the biological ability to perceive natural electrical stimuli. It has been observed only in aquatic or amphibious animals, since water is a much better conductor than air. Electroreception is used in electrolocation and for electrocommunication.- Overview :Electroreception is...
, as is much of the rest of its body. The elephantnose fish has poor eyesight and uses a weak electric field
Electric field
In physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...
, which it generates by muscular contractions, to find food, to navigate in dark or turbid waters, and to find a mate. Peters' elephantnose fish live to about 6-10 years, but there are reports of them living even longer.
In the aquarium
Peters' elephantnose fish is probably the most commonly-available Mormyrid in aquariumAquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
stores in the USA. In the aquarium (which should be at least 200 liters) it is timid, preferring a heavily planted environment with subdued lighting. Ideally, a pipe or hollow log should be provided. The substrate
Substrate (aquarium)
The substrate of an aquarium refers to the material used on the tank bottom. It can affect water chemistry, filtration, and the well-being of the aquarium's inhabitants, and is also an important part of the aquarium's aesthetic appeal...
should ideally be soft sand to allow the fish to sift through it with its delicate extended lip. It feeds on small worms (bloodworms) and aquatic invertebrates such as mosquito larvae, but in the aquarium will usually accept frozen or even flake food. How peaceful an elephantnose fish is can depend on the individual; some are quite aggressive with other species, while others are retiring. They may be kept in a community aquarium with peaceful species who share their water preferences. However, unless kept in an aquarium of over 400 liters, it is unwise to keep more than one elephantnose fish as they can be territorial. The conditions suggested to keep them in an aquarium are as follows: pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
of 6.8 to 7.2, water temperature 26 to 28 degrees Celsius, and water of medium hardness
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...
. The substrate should always be something that does not irritate the sensitive snout of the fish.
The weak electrical impulses generated by this fish can be made audible by placing two electrodes in the fish tank, which are then hooked up to an audio amplifier or a piezoelectric earbud. The sonar-like clicks that this fish emits can sound like a squeaky door when the fish is excited.
External links
- Peter Cain and Sapna Malwal, Landmark use and development of navigation behaviour in the weakly electric fish Gnathonemus petersii (Mormyridae; Teleostei), Journal of Experimental Biology, 205, 3915-3923 (2002), http://jeb.biologists.org/cgi/content/full/205/24/3915
- Photo (BBC News)
- http://sci-toys.com/scitoys/scitoys/biology/electric_fish/electric_fish.html Sci-toys.com instructions on making elephant nose electrical emissions audible.