Puffers are a remarkably unique fish.   True to their name, Puffers have the ability to puff themselves up to be nearly twice their resting size, sometimes as a stress response or as a fully functional defense tactic.  Potential predators do not attempt to swallow a puffed Puffer as it would prove fatal.  Puffers have large teeth, so they spend most of their time grazing the reef eating coral polyps and invertebrates.  For this reason, they aren't reef safe.  Puffers will eat a varied diet of meaty seafoods, pellets and flake foods.