''Schilbe intermedius'' or the silver butter catfish is a widespread species of African

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

. It seems closely related to '' Schilbe uranoscopus'' and these two species are sympatric over part of their ranges.

Distribution

Widespread in sub-Saharan Africa from the

Senegal River The Senegal River ( or "Senegal" - compound of the Serer term "Seen" or "Sene" or "Sen" (from Roog Seen, Supreme Deity in Serer religion) and "O Gal" (meaning "body of water")); , , , ) is a river in West Africa; much of its length mark ...

across to

Somalia Somalia, officially the Federal Republic of Somalia, is the easternmost country in continental Africa. The country is located in the Horn of Africa and is bordered by Ethiopia to the west, Djibouti to the northwest, Kenya to the southwest, th ...

and south as far as the

Pongola River The Phongolo River is a river in South Africa. It is a tributary of the Maputo River. It rises near Utrecht in northern KwaZulu-Natal, flows east through oPhongolo, is dammed at Pongolapoort, and crosses the Ubombo Mountains; then it flows nort ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

Biology

''Schilbe intermedius'' is a

potamodromous Fish migration is animal migration, mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few ...

catfish. It is reported to be a

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

species which occurs mainly in shallow waters and open waters of lakes, it migrates to the surface at night. Generally found in the lower reaches of river systems. It feeds on a fish, either swallowed whole or in pieces and a wide range of invertebrates including terrestrial insects. It is mainly

piscivorous A piscivore () is a carnivorous animal that primarily eats fish. Fish were the diet of early tetrapod evolution (via water-bound amphibians during the Devonian period); insectivory came next; then in time, the more terrestrially adapted rept ...

once it reaches 13–34 cm in length. ''Schilbe intermedius'' rarely grows to lengths greater than 30 cm. It breeds throughout the year peaking in the rainy season when it migrates into rivers in fairly compact schools to spawn in floodwater pools. In one study the most common prey item was redeye barb, a

cyprinid Cyprinidae is a Family (biology), family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barb (fish), barbs and barbel (fish), barbels, among others. Cyprinidae is the ...

, which made up 29% of all identifiable fish species sampled from the catfishes stomachs.

Description

There are two populations of the species one with and one without an

adipose fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

. The population lacking an adipose fin are from the north and west of Africa while the populations with an adipose fin are from the central, east and south of Africa. Quite distinctive with a large shovel mouth surrounded by 4-6 nasal barbs and the eyes slightly protrude from head. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

is long, extending from vent almost to the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. It has four pairs of short, barbels around the mouth. The ground colour is silvery, brownish to olive on the back and upper parts of the head. There are two dark grey to olive bands, the longest running along the lateral line from the upper gill cover to the caudal peduncle, where this band starts on the upper gill cover there is a dark humeral spot. The second shorter band runs from the beginning of the pectoral fins to the end of the

. The fins are transparent, although the anal fin has a dark band near the body and there is a dark streak which runs into each lobe of the deeply forked

Fisheries

''Schilbe intermedius'' is fished for food but tends not to be the primary target for fishermen who usually catch it when hunting for other species.

References

{{Taxonbar, from=Q3642172

intermedius The vastus intermedius () (Cruraeus) arises from the front and lateral surfaces of the body of the femur in its upper two-thirds, sitting under the rectus femoris muscle and from the lower part of the lateral intermuscular septum. Its fibers end ...

Fish described in 1832