If you look down into their tank they stare straight back up at you. and we discovered that if you hover your finger around them they'll jump up to grab it since they think it's food. It's painless, so I doubt they have teeth, or teeth big and sharp enough to be felt.
But I love 'em so much! When I go home to visit I play with them and change their water if they need it. They usually do. Their tank is disgusting half of the time.