The Not So Beautiful Porcupine Fish

By Chris Doyle on February 26, 2013 in Other

If a beauty pageant was held for all the animals in the ocean, there is no doubt that porcupine fish need not attend. Covered in spines and with mouths like parrots, they are not the most pleasant fish to look at. However, their unpleasant appearance comes with a distinct advantage – avoiding being eaten.

As an infinite number of MasterChef episodes have drummed into us, the key to a good dish is in the presentation. And it seems that rule holds true for wildlife as well. Porcupine fish have the ability to make themselves frighteningly ugly by inflating their bodies when threatened. They do this by rapidly ingesting water, which increases their size by up to three times and makes them take the shape of a ball. Once inflated, their spines, which usually lay flat against their skin, stand on end and become very prominent.

This act of self-inflation makes the fish look less appetising to anything that may be thinking of eating it. Not surprisingly, porcupine fish have very few predators.

For those predators daring enough to ignore their appearance, some species of porcupine fish are also poisonous to eat. They carry a potent neurotoxin in their internal organs that is over a thousand times more potent than cyanide. This toxin is produced by bacteria that the fish ingest as a part of their natural diet.

Porcupine fish eat hard-bodied animals such as crabs, clams, mussels and sea urchins. Their teeth are fused together into a plate, which enables them to crush through the hard shells. This also gives their mouth that beak-like appearance. Porcupine fish have thick, rubbery lips to protect them from the spines and broken shells of the prey they eat.

Porcupine fish are often mistakenly called puffer fish. While they are closely related to puffer fish, there are some notable differences between them. The most obvious one is that the spines of porcupine fish are much larger and always noticeable, whereas the spines of puffer fish are smaller and are only obvious when their bodies are inflated.

Porcupine fish are found in tropical and temperate seas all over the world. In Sydney, the most commonly found species is the three-bar porcupine fish. As the name implies, this fish have three prominent dark bars or bands on their skin – one under the eye, a second on the operculum and the third behind the pectoral fin.

While they look fearsome, porcupine fish are harmless to humans so long as they are not eaten. They usually hide out in caves and reef crevices during the day and come out at night to hunt, although they can sometimes be seen moving amongst kelp during the day.

If you do happen to see one, they are more likely to swim away and hide than inflate themselves. After all, to their eyes you look like you’ve hit more branches of the ugly tree than they have.