Puffer fish vary in size from one inch long pygmy puffer, to a two feet long freshwater giant puffer. Main feature, common for all puffer fish, is ability to ingest huge amount of water (and air sometimes) which increases their body size and turn them into odd-looking ball-like creatures. Quick transformation scares predators. Scientists believe that puffer fish developed this tactic as a method of the self-defense because they are poor swimmers that cannot escape from the danger quickly. Increase of the body size is not the only tactic used against the predators. Almost all species of puffer fish contain toxin (called tetrodotoxin) that can be 1200 times stronger than cyanide.