''Synodontis clarias'', known as the red tailed synodontis, or the mandi, is a species of

upside-down catfish The name upside-down catfish is most commonly used by aquarists to refer to the mochokid catfish '' Synodontis nigriventris'' alternately known to ichthyologists as the blotched upside-down catfish or false upside-down catfish. However, a number ...

that occurs widely in the waters of northern

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. It was first described by Swedish zoologist

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1758 as ''Silurus clarias''. The original specimens were obtained in Egypt, near

Cairo Cairo ( ; ar, القاهرة, al-Qāhirah, ) is the capital of Egypt and its largest city, home to 10 million people. It is also part of the largest urban agglomeration in Africa, the Arab world and the Middle East: The Greater Cairo metro ...

. The meaning of the

species name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''clarias'' is not certain, but may possibly have been used to mean "bright" or "clear".

Description

Like all members of the genus ''Synodontis'', ''S. clarias'' has a strong, bony head capsule that extends back as far as the first spine of the dorsal fin. The head contains a distinct narrow, bony, external protrusion called a humeral process. The shape and size of the humeral process helps to identify the species. In ''S. clarias'', the humeral process is subtriangular, flat, and rough. The fish has three pairs of

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the zebrafish, the black dragonfish and some ...

. The maxillary barbels are on located on the upper jaw, and two pairs of mandibular barbels are on the lower jaw. The maxillary barbel is straight with long, slender branches, with a broad membrane at the base. It extends about to 1 times the length of the head. The outer pair of mandibular barbels is about times as long as the inner pair, have long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of ''Syntontis'' species are hardened into stiff spines. In ''S. clarias'', the spine is as long or slightly longer than the head, curved, and serrated on both sides. The remaining portion of the dorsal fin is made up of seven branching rays, terminating in a short filament. The spine of the pectoral fin is shorter than the dorsal spine, and serrated on both sides. The adipose fin is 3 to times as long as it is deep. The anal fin contains five unbranched and seven to nine branched rays, and is acutely pointed in the front. The tail, or caudal fin, is deeply notched, with the upper lobe longer. All members of ''Syndontis'' have a structure called a premaxillary toothpad, which is located on the very front of the upper jaw of the mouth. This structure contains several rows of short, chisel-shaped teeth. In ''S. clarias'', there are relatively few premaxillary teeth arranged in one, two, or three distinct series. On the lower jaw, or mandible, the teeth of ''Syndontis'' are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". The number of teeth on the mandible is used to differentiate between species; in ''S. clarias'', there are about 6 to 9 teeth on the mandible. The color of the fish is grey to green on the back, white on the underside. The fins are greyish white and the tail is often tipped with red. Juveniles may have small dark marbling patterns on the body and round dark spots on the ventral, anal, and caudal fins. The maximum

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

of the species is . Generally, females in the genus ''Synodontis'' tend to be slightly larger than males of the same age.

Habitat and behavior

In the wild, the species is occurs from Senegal to Ethiopia, and along the entire length of the Nile River. The species is harvested for human consumption. Its habitat is threatened by dams, water depletion, and water pollution. In its natural environment, it is a bottom feeder, feeding on insect larvae, plants, and detritus. The reproductive habits of most of the species of ''Synodontis'' are not known, beyond some instances of obtaining egg counts from gravid females. Spawning likely occurs during the flooding season between July and October, and pairs swim in unison during spawning. The growth rate is rapid in the first year, then slows down as the fish age.

References

External links

{{Taxonbar, from=Q3760216 centralis Catfish of Africa Fish of Ethiopia Fish of Cameroon Fish of Chad Fish of Egypt Freshwater fish of West Africa Fish of Sudan Fish described in 1758 Taxa named by Carl Linnaeus