Sorubim is a small genus of long-whiskered catfish native to tropical South America.
[6] S. lima is the most widely distributed species of the genus, found east of the Andes in the Amazon, Orinoco, Paraná, and Parnaíba basins.
[2][8] Initially it did not occur in the upper Paraná basin above the Guaíra Falls, but these disappeared after the construction of the Itaipu Dam, allowing this species (and several others) to spread.
[2][8] S. maniradii was discovered in the Napo and Yasuni River drainages of Ecuador, but also occurs in other tributaries of the Amazon.
[12] Sorubim species are found in fast-moving and slow-moving waters, including lakes, rivers, and bays.
[3] S. elongatus occurs in both whitewater and blackwater, found in floodplain lakes and small creeks to large rivers.
[8] Sorubim species, like other catfish, possess dorsal and pectoral fin spines.
[4] Sorubim is characterized by a shovel-like, projecting upper jaw with an exposed, villiform (brush-like) premaxillary tooth patch.
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.
[4] Along with the lateral stripe, Sorubim species have a darkened dorsal surface, which is sometimes separated by a thinner, lighter-colored band.
This could provide camouflage when the fish are young and hiding among plant materials, and is lost when the adults live in more open water habitats.
[5] S. cuspicaudus has a markedly different tail (straight, pointed, and long) in contrast to the other Sorubim with more rounded caudal fin lobes.
[5] S. elongatus has an elongated head and body, and appears rather slender in comparison to the other members of this genus.