Teeth and bones and fins. That is what piranhas are made of. I once learned it the hard way, trying to fish for a living in the Amazon. They do not make a proper or tasty meal. I tried my best to catch arapaimas and arawanas, but all I got was piranhas. Over and over again, while our base manager miraculously pulled up delicious fish out of the living fish soup that was the Amazon in dry season. Most of the time the piranhas chewed off my bait so I lost the hook and sinker, too. I often wondered whether our base manager was using a spell or a mantra before throwing out his fishing line. Even if we were performing the exact same action I was obviously doing something wrong.
There are impressive piranha teeth – and there are possibly even more impressive sawfish teeth. Why keep your teeth in your mouth when you can grow a jaw outside of your skull and place your teeth around its outer lining? Much easier to stun and cut prey, yes? (Aquarium of Genoa, Genoa, Italy; July 2018)