Porcupinefish (assorted)

Porcupinefish is a common name, not a single species. Wikipedia describes the Diodontidae as a family of medium-to-large fish in the order Tetraodontiformes, also called blowfishes and sometimes balloonfishes and globefishes, with about 18 species. The World Register of Marine Species (WoRMS) lists Diodontidae as an accepted family. This group entry covers sightings where the species was not recorded.

Wikipedia says they are sometimes called pufferfishes, but are not the closely related Tetraodontidae, which more commonly carry that name. Their upper and lower teeth are fused into a beak like a parrot's.

A conservation status is not given here, because this entry covers a whole group.

Wikipedia says porcupinefishes are found in shallow, temperate and tropical seas worldwide, and that a few species live much further from shore, where schools of thousands can occur.

Where Divers Find Them

At Amed, Bali, Evolution Diver lists porcupine fish at the Japanese Wreck, and bali.live says porcupine fish are among the animals found at the same wreck. Neither says which species, or how often.

Wikipedia says porcupinefishes are generally slow-moving. They can inflate their bodies by swallowing water or air, which nearly doubles their height and raises sharp spines; they use their beak to eat molluscs and sea urchins. Some species carry tetrodotoxin in internal organs such as the ovaries and liver. Wikipedia says adults have few predators, though sharks and orcas sometimes take them.

Underwater Encounter Behavior

The sources cited here do not describe how porcupinefishes react to divers.