Suru: Surubi have smooth skin, and show three distinctive pairs of chins, two next to the chin and one of considerable length next to the jaw. Some surubi 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 deep and slow water areas, and at night they enter streams to feed.