Question: Are Piranhas Dangerous?
Answer: A really hungry Piranha will bite most anything, even his own kin. However, Piranha normally feasts on other species of fish or wounded animals -- not humans. In fact, more piranhas are eaten by people then people are eaten by piranhas. Although I haven't had the pleasure of eating piranha myself, people in some areas of South America eat them regularly and say they are quite tasty.
How Dangerous Are They?
Fish expert, Dr. Axelrod, once stated on network television that piranhas are not dangerous to people. Later he was dared to prove it, and prove it he did. He waded into piranha infested waters wearing only swim trunks. Placing a large piece of meat on a fishhook, he dangled it in the water and waited to see what happened. The piranha tore into the meat but not Dr. Axelrod. Although I wouldn't recommend reaching in the tank to pet your piranha, as long as they are well fed they aren't likely to bite you.
Are Piranhas Legal?
Even though piranhas are not endangering humans, they do present a danger to native fish. For that reason many states restrict importing, breeding, or even keeping them in an aquarium. Why? Unfortunately people have, and will, dump fish they don't want into rivers or lakes. A piranha tossed into river or lake an easily fish that are supposed to live there, thus damaging the ecology.
Should You Keep Them?
Piranhas are not the most ideal aquarium fish. They can't be kept with other fish, because they would eat them. Unless your tank is bare, you won't see them out and about often, because they are rather skittish and hide a good deal of the time. Feeding time is when you will see the most action, and even then they may wait for you to leave the room before they feed.
If you are serious about wanting to keep piranha, study what they need to stay healthy. Piranhas are carnivores that prefer their food live. They need a quiet habitat with places to hide, and should not be kept with other fish, even their own species. Because of the danger they present to local habitats, piranhas are not legal in many states, so check your local laws before trying to bring one home.