Piranhas live up to their Hollywood reputation as vicious fish that will not hesitate to chew off the hand that feeds it. This isn't a pet for the faint of heart – only experienced aquarists should take on the piranha.

In the home aquarium, piranhas (Serrasalmus nattereri) will reach about 8 to 10 inches in length if given enough room. They have a silvery-gold color, a red throat, and a mouth full of razor sharp teeth designed for tearing flesh. They are found naturally in the waters of South America and Guyana and it is illegal to import or export them in many countries.

These are dangerously aggressive fish. Piranhas live in schools, which further enhances their aggression. Frenzied feeding behavior excites the fish in the school and prey can be devoured in seconds. Individual fish are less aggressive then those that live in schools, but they will still attack if they are distressed or frightened. Because of a lack of socialization, piranhas raised as single fish cannot be added to a group at a later time.

These fish eat only meat and their preference is live prey. Feeder goldfish, minnows and earthworms are usual food sources. Beef heart, or fish fillets may be accepted. Resist the temptation to hand feed these fish; they can easily bite a finger and leave a serious wound.

To learn more about what it takes to care for these fish, see the story Choosing a Piranha.