The pufferfish is carnivorous, with a preferred diet of algae and various invertebrates, and less frequently shellfish. The animals that are part of the pufferfish's diet contribute to the pufferfish's poison by providing bacteria.
Pufferfish are primarily found in an oceanic environment, but small numbers are found outside of saltwater bodies. The largest of the pufferfish species does not exceed 3 feet in length, while the smallest species is a fraction of that size. The pufferfish contains a potent kind of toxin, and a great amount of it. This toxin is fatal to the fish's natural predators, and to humans.