The Manguruyú, jaú call in Brazil is the fish but great of Argentina , some stories make references to fish near 200 kgs., although with certainty it knows that they surpass the 160 kg . In Brazil some were fished that, eviscerados and without head, weighed 150 kilos; in that same country females were observed whose ovaries (that lodged almost three million and means of eggs) weighed more than four kilos. The stories of fishermen are frequent who "have been towed" in their boat by these great fish, so is the power of their swimming.

Tree trunk is a siluriforme of body very, reason why, although the surubí surpasses it in length, this one surpasses it in weight. It has a very wide head and low, the chins maxilares are cylindrical and are shorter or equal at the top. In the young people they arrive at the aim of the ridge. The mentonianas, until the eye and the postmentonianas until the origin of the pectoral ones. the adults are of color dark coffee, whereas the young people are gray-yellowish, with dark spots in form of Or or C in the back and the fatty fin.

The manguruyú frequents wide mighty rivers and deep in which it chooses great pozones located immediately after the tracks to take advantage of the smaller units of other species than arrive at pozón deteriorated by the current forts. The boat will have to derive from the track towards pozón dragging the baits that will be similar to those of the fishing of the surubí.