About the Puffer Fish

Physical Characteristics

• When they are not puffed up, the 120-plus species of puffer fish have narrow bodies with bulging heads. Some species can grow to more than 2 feet long; the smallest are a diminutive 2 or 3 inches. Many puffer fish contain a toxin, tetrodotoxin, which is lethal to many animals, including humans. The coloring varies greatly among species. Some puffer fish have bright colors to show they are toxic; others have subdued, mottled colors that camouflage them against the ocean floor. Many species are covered with spines, which provide yet another layer of defense. Puffer fish need all these defenses because they are relatively slow swimmers and would otherwise be vulnerable to predators.

Habitat and Distribution

• Most puffer fish inhabit warm tropical or subtropical seas. There are a few freshwater species and a few that prefer the brackish water of estuaries.

Life Cycle

• Puffer fish are egg layers. In many species, a parent -- usually the male -- guards the eggs until they hatch. The fry, or baby puffer fish, often join the zooplankton in the open ocean before returning to coastal habitats as they mature.

Danger to Humans

• People eat puffer fish with the risk perhaps being one of the attractions. Not all of a puffer fish contains the toxin. Normally only the liver, reproductive organs, intestines and skin contain lethal amounts of tetrodotoxin. If prepared properly, the fish is edible. If prepared improperly, it is deadly, and people die every year from puffer fish poisoning.

Conservation Issues

• People pose a serious threat to puffer fish. Deliberate fishing of puffer fish, accidental bycatch, habitat destruction and pollution have led to several species becoming threatened, including Tetraodon pustulatus, a freshwater puffer fish. Puffer fish are caught for their meat or to make novelty items such as lamps. Some of the smaller species, such as the Fiji blue dot toby puffer (Canthigaster epilamprus), have become popular aquarium fish. The taking of wild puffer fish for the pet trade leads to additional conservation problems.