Long-spine porcupinefish

The long-spine porcupinefish (Diodon holocanthus), also known as the balloonfish, freckled porcupinefish, porcupine puffer, and porcupine pufferfish, is a species of marine fish in the family Diodontidae.^[2]

Long-spine porcupinefish
Diodon holocanthus at the Audubon Aquarium
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Tetraodontiformes
Family:	Diodontidae
Genus:	Diodon
Species:	D. holocanthus
Binomial name
Diodon holocanthus Linnaeus, 1758
Distribution of the long-spine porcupinefish

Description

Conventional and X-ray images of Diodon holocanthus

The long-spine porcupinefish is pale in color with large black blotches and smaller black spots; these spots becoming fewer in number with age. It has many long, two-rooted depressible spines particularly on its head. The teeth of the two jaws are fused into a parrot-like "beak". Adults may reach 50 cm (20 in) in length.^[3] The only other fish with which it might be confused is the black-blotched porcupinefish (Diodon liturosus), but it has much longer spines than that species.^[4]

Diet

The long-spine porcupine fish is an omnivore that feeds on mollusks, sea urchins, hermit crabs, snails, and crabs during its active phase at night.^[5] They use their beak combined with plates on the roof of their mouths to crush their prey such as mollusks and sea urchins that would otherwise be indigestible.^[6][7]

Distribution

The long-spine porcupinefish has a circumtropical distribution, being found in the tropical zones of major seas and oceans:

• In the Atlantic it is found from Florida and the Bahamas to Brazil and in the Eastern Atlantic from 30°N to 23°S, as well as around South Africa.
• And In the western Indian Ocean from the southern Red Sea to Madagascar, Réunion and Mauritius.
• Also In the Pacific Ocean from southern Japan to Lord Howe Island, and east to the Hawaiian and Easter islands. Also from southern California to Colombia and the Galapagos Islands.^[8]

Habitat

Diodon holocanthus hiding within a reef in Oman

They are found over the muddy sea bottom, in estuaries, in lagoons or on coral and rocky reefs around the world in tropical and subtropical seas.^[9]

Spawning

Young Diodon holocanthus in an aquarium

Spawns at the surface at dawn or at dusk in pairs or in groups of males with a single female; the juveniles remain pelagic until they are at least 7 cm (3 in) long.^[3] Young and sub-adult fish sometimes occur in groups.