Electric catfish
Encyclopedia
Electric catfish is the common name for the catfish
(order
Siluriformes) family
Malapteruridae. This family includes two genera
, Malapterurus
and Paradoxoglanis
with 19 species
. Several species of this family have the ability to produce an electric shock of up to 350 volt
s using electroplaques of an electric organ
. Electric catfish are found in tropical Africa
and the Nile River. Electric catfish are usually nocturnal and feed primarily on other fish, incapacitating their prey with electric discharges.
with elongate posterior chambers, two chambers in Malapterrus and three in Paradoxoglanis.
It is one of the few electric species that have been conditioned by means of reward to discharge on signal. As reported in the New York Times, April 2, 1967, a researcher, Dr. Frank J. Mandriota of City College, NY, conditioned a M. Electricus to discharge on a light signal for a reward of live worms delivered automatically. This is a first in conditioning that modified neither glandular nor muscular responses.
They can grow as large as 100 centimetres (39 in) SL
and about 20 kilogram
s (44 lb
) in weight
. All Paradoxoglanis species are much smaller. Most malapterurids are dwarf species less than 30 cm (12 inches) long.
ians. Stories say that the Egyptians used this type of catfish when treating some nervous diseases. They would use only smaller fish, as a large fish may generate an electric shock of up to 300 or 400 volts. The Egyptians have depicted the fish in their mural paintings and elsewhere; the first known depiction of an electric catfish is on the slate palette of the pre-dynastic Egyptian ruler Narmer
, about 3100 BC. An account of its electric properties was given by an Arab physician of the 12th century; then as now the fish was known by the suggestive name of Raad, abo el ra3ash,el ra3ad or Raash, which means thunder (literally trembler, shaker).
Though the shock an electric catfish can generate is not known to be fatal to humans, the catfish does use its electricity as a weapon to ward off predators.
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
(order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Malapteruridae. This family includes two genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, Malapterurus
Malapterurus
Malapterurus is a genus of catfishes of the electric catfish family . It includes sixteen species.-Distribution:The genus Malapterurus is found throughout western and central tropical Africa and the Nile River...
and Paradoxoglanis
Paradoxoglanis
Paradoxoglanis is a genus of electric catfishes . It includes three species, P. caudivittatus, P. cryptus, and P. parvus....
with 19 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. Several species of this family have the ability to produce an electric shock of up to 350 volt
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
s using electroplaques of an electric organ
Electric organ
In biology, the electric organ is an organ common to all electric fish used for the purposes of creating an electric field. The electric organ is derived from modified nerve or muscle tissue...
. Electric catfish are found in tropical Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and the Nile River. Electric catfish are usually nocturnal and feed primarily on other fish, incapacitating their prey with electric discharges.
Description
Malapteruridae is the only group of catfish with a well-developed electrogenic organ; however, electroreceptive systems are widespread in catfishes. The electrogenic organ is derived from anterior body musculature and lines the body cavity. Electric catfish do not have dorsal fins or fin spines. They have three pairs of barbels (the nasal pair is absent). The swim bladderGas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...
with elongate posterior chambers, two chambers in Malapterrus and three in Paradoxoglanis.
It is one of the few electric species that have been conditioned by means of reward to discharge on signal. As reported in the New York Times, April 2, 1967, a researcher, Dr. Frank J. Mandriota of City College, NY, conditioned a M. Electricus to discharge on a light signal for a reward of live worms delivered automatically. This is a first in conditioning that modified neither glandular nor muscular responses.
They can grow as large as 100 centimetres (39 in) SL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
and about 20 kilogram
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
s (44 lb
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...
) in weight
Weight
In science and engineering, the weight of an object is the force on the object due to gravity. Its magnitude , often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus:...
. All Paradoxoglanis species are much smaller. Most malapterurids are dwarf species less than 30 cm (12 inches) long.
Relationship to humans
The Nile fish was well known to the ancient EgyptAncient Egypt
Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...
ians. Stories say that the Egyptians used this type of catfish when treating some nervous diseases. They would use only smaller fish, as a large fish may generate an electric shock of up to 300 or 400 volts. The Egyptians have depicted the fish in their mural paintings and elsewhere; the first known depiction of an electric catfish is on the slate palette of the pre-dynastic Egyptian ruler Narmer
Narmer
Narmer was an ancient Egyptian pharaoh of the Early Dynastic Period . He is thought to be the successor to the Protodynastic pharaohs Scorpion and/or Ka, and he is considered by some to be the unifier of Egypt and founder of the First Dynasty, and therefore the first pharaoh of unified Egypt.The...
, about 3100 BC. An account of its electric properties was given by an Arab physician of the 12th century; then as now the fish was known by the suggestive name of Raad, abo el ra3ash,el ra3ad or Raash, which means thunder (literally trembler, shaker).
Though the shock an electric catfish can generate is not known to be fatal to humans, the catfish does use its electricity as a weapon to ward off predators.