The Surubi have smooth skin, and display three distinctive pairs of barbels, two next to the chin and one of considerable length next to the maxilla. some surubíes managed to reach a length of 1.8 m and a weight of 90 kg. The two largest species are Pseudoplatystoma tigrinum and Pseudoplatystoma corruscans. The latter is the one that reaches the largest size, and is identified by having black spots on its flanks. They are large predators, and feed mainly on juveniles of other species. They spend the day in areas of deep and slow water, and enter streams at night to feed.