Most of the adult porcupinefishes are found inshore and most of the juveniles are pelagic. Among the slowest of fishes, they appear to buzz slowly through the water. They are found on rocky and coral reefs, and over sand, weed, or sponge-covered bottoms to depths of 150 m. They feed on hard-shelled benthic invertebrates which are crushed with their powerful beak-like jaws. Most adults are solitary and nocturnal. They are thought to have toxic flesh.
There are 7 genera and about 18 species worldwide. Malaysia has about 4 species.