No fish were harmed in the making of these photos... I took my kids piranha fishing in the Amazon and our guide is just using the soft side of his pocket knife to show us the teeth of a beauty my daugher caught. We learned that they aren't dangerous to humans unless you're caught in a feeding frenzy and that mostly they prefer to eat seeds and such so that's why they need such sharp teeth.
Later on that afternoon, just to test that theory, we all went swimming in this same lake! :-)
I was inspired to post this after watching the Planet Earth program on Discovery on Sunday. They really sensationalized the behavior of these guys. I hate it when they do that. Anyway, for those of you who saw it... here's one up close from a lake just like the one on the show.