Sorubim is a small genus of long-whiskered catfish native to tropical South America. A number of characteristics allows the differentiation of each species in the genus. Sorubim are important food fish in South America and are highly significant to fisheries of some areas; however, harvests of these fish are not identified as much as other, more popular food fishes such as Colossoma, Arapaima, and Brachyplatystoma. Some species of this family are popular aquarium fish. More subspecies of this fish are S. lima, S. Trigonocephalus, S. Cuspicaudus, S. Maniradii and S. Elongatus.
Sorubim, like other catfish, possess a dorsal and pectoral fin spines. They have a triangular adipose fin. As Pimelodidae, these fish have very long barbels, especially maxillary barbels, which range in length from reaching the pectoral fin to extending past the pelvic fins. Like some other Pimelodid genera, these fish may have long filaments on their dorsal, pectoral, and caudal fins; in juveniles, these filaments may be even longer than the body. Sorubim is characterized by a shovel-like, projecting upper jaw with an exposed, villiform (brush-like) premaxillary tooth patch. The head is depressed and usually three times longer than it is wide. The eyes are set laterally and usually visible from below. They have a characteristic black, lateral stripe, variable in width, that extends from the snout to the end of the caudal fin; though this may seem minor, no other Pimelodid has a lateral stripe that reaches down the entire length of the head and body.
Along with the lateral stripe, Sorubim species have a darkened dorsal surface, which are sometimes separated by a thinner, lighter-colored band. The dorsal surface may change its shade quickly with its surroundings. Sorubim lima may also display dark blotches or spots on its dorsal surface. The ventral part of the body is white or cream colored. Light areas may appear golden or slate gray, often appearing iridescent. Young fish are more heavily pigmented than adults. Posterior-most rays on dorsal, anal, and pelvic fins are elongated, darker, and heavily speckled with chromatophores; however, this speckling is reduced in the adults. This could provide camouflage when the fish is young and hiding among plant materials, and is lost when the adults live in more open water habitats.
Sorubim's habit of attacking artificial lures and then fighting like tuna, makes it endearing to peacock bass anglers and catfishermen alike. They tend to congregate and forage at the edges of shallow beaches with nearby drop-offs to deeper water. Small live bait or pieces of cut bait are effective when cast onto the beach and allowed to drift naturally to the nearby drop-off. An effective rig consists of a 10/0 to 14/0 circle hook with a wire leader and relatively light sinker , enough to keep it down while still allowing the current to slowly carry it. Once hooked, Sorubim will fight in open water with strong runs and surprising stamina.
Sorubim is a widely distributed genus, collected from many major river basins and ten countries. It is the most widely distributed species of the genus, found east of the Andes in the Amazon, Orinoco, Parana, and Parnaiba basins and also the upper Amazon drainage of Brazil, Ecuador, Peru, and Bolivia. It was discovered in the Napo and Yasumi River drainages of Ecuador, but also occurs in other tributaries of the Amazon.