The group of pirañas and palometas represents a good amount of species very seemed to each other, that they have in common a life in group and a high aggressiveness. Piraña is described this here for being the one that is but it frequents in the river basin of the Silver, although also is in the amazons.

These fish have the body of less oval form but, very compressed laterally, a powerful head with maníbula and mouth provided with teeth very sharpened that altogether give a ferocious aspect him. The teeth continuously replace in both maxilares facilitating their possibilities of feeding. They are fed on alive prey and in many cases they determine the presence or they influence in the distribution and feeding of other fish. They are inflamed before wounded of greater animals and altogether they can reduce an organism to only his bones in very just a short time. Its stature oscillates between the 15 and 25 cm , although usually they remove greater units.

The fishermen of other species and that fishes with bait, often see frustrated their fishing since pirañas eats the bait. They take any artificial one and with light pack light field equipment very they do a fishing amused.