White-Spotted Puffer (Arothron hispidus): Pufferfish Facts

What does a white-spotted puffer look like?

The white-spotted puffer has the classic pufferfish shape: a short, thick, rounded body, a broad head, large eyes and a small mouth. Its body is grayish-brown to greenish-brown, scattered with small white spots across the back, the sides and the tail. The belly is pale and marked with stripes, which is why the fish is sometimes called the stars-and-stripes puffer.

Two features help divers recognize it. Around each eye and around the dark patch at the base of each pectoral fin run rings of alternating white and dark lines, like ripples around a stone dropped in water. Each nostril also carries two small, fleshy tentacles, a feature of the genus Arothron.

Like other pufferfishes, it has no normal scales. Instead, its skin is covered in tiny prickles everywhere except around the snout and the base of the tail. These prickles lie flat when the fish is relaxed and stand out when it inflates. The species name hispidus means “bristly” or “rough” in Latin.

How big does a white-spotted puffer get?

The white-spotted puffer is one of the larger pufferfishes. It grows to about 50 cm (20 in) long, and the heaviest published weight is about 2 kg (4.4 lb). Most pufferfishes are small to medium-sized fish, and only a few species grow longer than about 50 cm.

Its close relatives in the order Tetraodontiformes include the porcupinefishes, triggerfishes, boxfishes and the ocean sunfish, one of the heaviest bony fish in the world.

The pufferfish family, Tetraodontidae, contains roughly 190–200 species. Most live in warm coastal seas, but about 35 species spend their whole lives in fresh water in South America, Africa and Southeast Asia. Their closest relatives, the porcupinefishes, can also inflate but carry long, obvious spines, while the prickles of puffers such as the white-spotted puffer are small and mostly hidden until the fish swells up.

Where does the white-spotted puffer live?

The white-spotted puffer has one of the widest ranges of any reef fish. It is found from the Red Sea and the coast of East Africa across the Indian Ocean and the tropical Pacific, north to southern Japan and the Hawaiian Islands, and south to Lord Howe Island off Australia and Rapa in French Polynesia. It also occurs on the far side of the Pacific, where it lives from Baja California and the Gulf of California south to Panama.

In 2018 a single white-spotted puffer was confirmed for the first time in the eastern Mediterranean Sea. Many Red Sea fish have entered the Mediterranean through the Suez Canal, but how this individual arrived is not known.

It lives in shallow water, usually from about 1 m to at least 50 m (3–165 ft) deep. Adults are found on outer reef slopes, reef flats and lagoons, often over sand or rubble between coral heads, and in coastal bays near rocky reefs. Young fish are common in weedy parts of estuaries and in shallow areas with seagrass.

What does the white-spotted puffer eat?

The white-spotted puffer is an omnivore with a remarkably broad diet. It eats fleshy algae and hard, chalky coralline algae, along with detritus, and many kinds of invertebrates: sponges, corals, zoanthids (small relatives of sea anemones), sea squirts, snails, clams, crabs, tube worms, sea urchins and starfish.

Its main tool is its beak. Pufferfishes are named Tetraodontidae, from Greek words meaning “four teeth”, because their teeth are fused into four strong plates, two in the upper jaw and two in the lower. The joined plates form a parrot-like beak that can crack shells, crush crabs and bite off pieces of coral. The fish usually feeds alone, picking over the reef and the sand around it.

How do pufferfishes swim and puff up?

Pufferfishes are slow swimmers. Instead of beating the tail like most fish, a white-spotted puffer moves mainly by flapping its pectoral, dorsal and anal fins, which makes it very maneuverable but not fast. The tail works mostly as a rudder, although the fish can sweep it for a sudden burst of speed when startled. Pufferfishes can also move their eyes independently, which helps them watch for danger. Good eyesight and a quick getaway are a puffer’s first line of defense, and inflating is the backup when escape fails.

When a predator gets too close, the puffer has a second line of defense. It rapidly gulps water into its extremely stretchy stomach until its body swells to a much larger, almost round ball covered in prickles, too big and awkward for many predators to swallow. Pufferfishes have no ribs and no pelvic bones, which leaves room for the body to expand. How this works, and what it costs the fish, is explained in Why do pufferfish puff up?

Is the white-spotted puffer poisonous?

Yes. Like many pufferfishes, the white-spotted puffer carries tetrodotoxin, a powerful nerve poison that blocks the signals sent along nerves and can paralyze muscles. In pufferfishes the toxin is concentrated mostly in the liver and ovaries, with smaller amounts in the skin and gut, and the flesh of the white-spotted puffer has been reported as highly toxic. FishBase lists the species as poisonous to eat.

Most evidence suggests that the toxin is not made by the fish itself but by bacteria, and that it builds up in pufferfishes through their food. Pufferfishes are protected from their own toxin by changes in the sodium channels it normally blocks and by proteins that bind it. The toxin is a defense, making the puffer a dangerous meal, and it may explain why some pufferfishes are boldly patterned and make little effort to hide. The risks to people and the history of fugu are covered in Are pufferfish poisonous?, and the species is compared with other toxic animals in most poisonous animals.

Behavior and daily life

Adult white-spotted puffers are usually solitary and territorial, each fish keeping to an area of sand and rubble on or near the reef. They are often seen by divers and are popular subjects for underwater photographers.

Like many reef fish, white-spotted puffers visit cleaning stations, spots on the reef where small cleaner fish such as cleaner wrasses pick parasites and dead skin from larger fish. In Hawaii, white-spotted puffers are often photographed being cleaned by the Hawaiian cleaner wrasse, a species found only in those islands.

Pufferfishes can also change the intensity of their colors and patterns, for example becoming paler or darker depending on their surroundings or mood.

Reproduction and life cycle

Surprisingly little is known about how the white-spotted puffer breeds in the wild. Like other pufferfishes, it reproduces by laying eggs. Many marine pufferfishes release eggs into the water or lay them on the bottom, and their tiny larvae drift in the open sea for a time before settling on reefs or in coastal nurseries.

Young white-spotted puffers are common in sheltered, weedy estuaries and seagrass areas, while adults live mainly on and around reefs. Young fish have fewer and less complete rings around the eyes than adults. In some pufferfishes, even the larvae are protected by tetrodotoxin on the surface of their skin, which makes predators spit them out.

How long white-spotted puffers live in the wild has not been well studied.

Predators and conservation status

Adult white-spotted puffers have few natural enemies, thanks to their size, their ability to inflate and their toxin. Some predators, however, are known to eat pufferfishes, including certain sharks and lizardfishes, which seem able to cope with the toxin.

The IUCN lists the white-spotted puffer as Least Concern, in an assessment carried out in 2011 and published in 2014. The species is widespread and common across a huge range, and it is found in many marine protected areas. It is collected for public aquariums and the aquarium trade and caught in small numbers in local fisheries, but these activities are not thought to threaten the species as a whole. Like all reef animals, however, it depends on healthy reefs, lagoons and estuaries, which are under pressure from pollution, coastal development and the warming of the oceans.

White-spotted puffers and people

For divers and snorkelers in places such as the Red Sea, the Maldives, Southeast Asia and Hawaii, the white-spotted puffer is a familiar and well-loved sight, often hovering curiously near the reef. It is also displayed in many public aquariums in Europe and North America.

It should never be eaten. Pufferfish poisoning has killed people in many countries, and because the amount of toxin varies between species, individuals and seasons, there is no reliable way for a nonexpert to tell whether a pufferfish is safe. Anyone who feels numbness or tingling of the lips or mouth after eating pufferfish should call emergency services immediately: 911 in the US, 112 in the European Union or 999 in the UK.