Watercolours on paper
'Porcupine Fish' from William Buleow Gould's Sketch book of Fishes in Macquarie Harbour c 1832
This was bought at the Australian National Maritime Museum, Darling Harbour, Sydney in 2012
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Porcupinefish are fish of the family Diodontidae, also commonly called blowfish or pufferfish.
Porcupinefish have the ability to inflate their body by swallowing water or air, thereby becoming rounder. This increase in size (almost double vertically) reduces the range of potential predators to those with much bigger mouths. A second defense mechanism is provided by the sharp spines, which radiate outwards when the fish is inflated.
Some species are poisonous, having a tetrodotoxin in their internal organs. This neurotoxin is at least 1200 times more potent than cyanide. The poison is produced by several types of bacteria that are obtained via the fish's diet. As a result of these three defenses, porcupinefish have few predators, although adults are sometimes preyed upon by sharks and orcas. Juveniles are also preyed on by tuna and dolphins.