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Home › Sea Wildlife Facts › Marine Species › Vertebrates › Globefish

Interesting Facts about Porcupinefish

[Blowfish Phylum: Chordata] [Class: Actinopterygii] [Order: Tetraodontiformes] [Family: Diodontidae]

At least 16 recognised species of porcupinefishes belong to the family Diodontidae and they can be further divided into two main genera (Diodon and Chilomycterus).

This section contains some unusual facts about porcupine fish, including where they are found, what they eat, and how they reproduce.

Distribution and Habitats of Porcupinefishes

Porcupine fish are a circumtropical marine species so the best places to find them are:

• Some parts of the Atlantic Ocean (especially Bermuda, the Caribbean, Brazil)
• Indo-Pacific regions (e.g., Australia, Hawaii, East Africa, the Red Sea, Southeast Asia)
• Eastern Pacific Ocean (California coastline, most of the offshore islands, and Peru)

They flourish best in the warm and subtropical seas of coastal marine environments. Porcupinefish habitats include coral reef networks, rubble and rocky outcrops down to fifty (50 metres, with shallower sandy seagrass beds often inhabited by juveniles.

Porcupinefish Characteristics and Behaviour

One of the distinct traits of all porcupinefish species is being able to inflate their body. They ingest water (or air) to become a bloated balloon shaped sphere.

An inflated spiny puffer with erectile spines on the outside is much more difficult for predators to swallow, sharks and killer whales for example.

Plus, many of the species contain a powerful nerve poison called 'tetrodotoxin', usually contained in the liver, skin, and internal organs.

Here's the thing:

Like their close relatives the pufferfishes (Tetraodontidae), the fused teeth inside the mouth of both species create a 'parrot-like' beak structure.

But, puffers have four fused teeth (2 more than porcupine fish) that they use to crush hard-shelled prey, such as clam shellfish and other types of armored mollusks.

When it's not inflated, the porcupine fish body shape is somewhat rounded and oblong. As a consequence of that, they move around quite slowly and they tend to be a little cumbersome when they swim.

Porcupinefish Size and Weight

Some blowfish species have bright body colouration that acts as a warning about their toxicity. Many are solitary creatures and they can also be territorial in nature. Some of the males are known to guard their feeding areas and nesting sites.

The smallest porcupine fish is the dwarf puffer (Carinotetraodon travancoricus) which rarely grows more than three (3) centimetres long.

By comparison, the spot-fin porcupinefish (Diodon hystrix) is one of the biggest in the species. Fully grown adults can grow to ninety (90) centimetres long (3 feet) and weigh close to three (3) kilograms.

Pro Tip: Being called a puffer fish is not one of the most inappropriate fish names used in marine biology. In fact, it has a defencive response of puffing itself up to three times its normal size when it feels threatened. Thus, being able to suck in huge amounts of water to temporarily increase their size is why their common names also include the balloonfish, blowfish, and globefish.

What Do Porcupinefish Eat?

Most species of porcupine fish with the scientific name Diodontidae are nocturnal durophagous predators, meaning they feed mostly on 'chitin reinforced' shelled invertebrates, such as:

• Barnacles
• Clams
• Crabs (especially hermit crabs)
• Detritus matter
• Mussels
• Sea snails
• Sea urchins
• Shrimp
• Small aquatic crustaceans
• Small fish (not common)
• Worms

Some colourful pufferfishes also supplement their daily diet by grazing on various types of plant matter, such as algae, coral polyps, and sea sponges.

Types of Porcupine Fish Species

How Do Porcupinefish Reproduce?

Even though the reproductive behaviours of different puffer fish vary by species, the courtship and mating rituals share some common characteristics. For example, most porcupine fish reproduce through a process of external fertilisation.

During the mating season, males can be seen courting females by swimming around them or giving them gentle nudges.

By and large, the male will lead his female to a suitable spawning site, which is usually open sand or a sheltered location.

In case you were wondering...

When spawning occurs, a female lays her spherical "sticky" eggs directly into the open water or onto a suitable substrate, such as plants or rocks. The male attempts to fertilise them by scattering his sperm over them.

Parental care tends to vary according to different species. Even though some exhibit no parental care whatsoever, abandoning the eggs to develop on their own, others will guard their eggs until they hatch.

Hatching usually takes place within a few days, slightly longer if the water temperature fails to warm up. Puffer fish larvae are minute and planktonic, meaning they drift in the water column until they have grown big enough to find a suitable place to settle down.

Porcupinefish Predators and Threats

Pufferfish are not aggressive towards humans. In fact, they tend to be quite friendly with scuba divers who like to observe their comical swimming actions and large beady eyes - which can actually move independently of each other.

In the wild, pufferfishes have many natural predators, especially groupers, sharks, Mahi Mahi (dolphin fish), large tuna fish, and even some marine mammals.

Apart from that, some of the worst human-induced threats to their survival include:

• Climate change (resulting in varying degrees of coral bleaching).
• Overfishing (particularly in countries where pufferfish (fugu) is considered a culinary delicacy).
• Underwater garbage pollution.
• Habitat degradation and destruction (e.g. mangrove clearance for aquaculture).

Pro Tips: The IUCN Red List of Threatened Species assessed many of the porcupinefish family as "Least Concern" (LC). But, they list the Malabar Pufferfish (Carinotetraodon travancoricus) as "Vulnerable" (VU) and the Japanese Pufferfish (Takifugu rubripes) as "Near Threatened" (NT).

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