Balloonfish in Galápagos: Facts and Where to See It

Porcupinefish have two lines of defence. First, they can inflate their bodies by swallowing water or air, becoming almost twice as tall. That leaves only predators with much larger mouths able to swallow them. Second, their sharp spines, which normally lie flat, radiate outwards when the fish is inflated.

• Look. The balloonfish is pale with large black blotches and smaller black spots; the spots become fewer as it ages.
• Spines. It has many long spines with two roots each, especially on the head, and can fold them down.
• Beak. Its upper and lower teeth are fused into a beak like a parrot's, which, with plates on the roof of the mouth, crushes shells and sea urchins.

Balloonfish live in tropical and subtropical seas around the world: over muddy bottoms, in estuaries and lagoons, and on coral and rocky reefs. Their active phase is at night, when they feed on shelled prey such as molluscs and sea urchins. Charles Darwin mentioned a porcupinefish in his account of the voyage of the Beagle.

Guide sighting records list one site: Devil's Crown, a snorkelling site off Floreana, rated Rare. Scan the rocky bottom and the ledges slowly; a spotted fish holding still is easy to overlook.

The guide records list the balloonfish at Devil's Crown in every month. In the next twelve months, 42 departures stop at the site.

No, it is listed as Least Concern and lives in warm seas worldwide. In Galápagos, park rules ask visitors to keep at least 2 metres (6 feet) from wildlife.

1. Trying to make it puff up. Keep your distance and let it be.
2. Handling it. The spines are sharp, and some porcupinefish carry a strong toxin in their organs.
3. Calling it a pufferfish. Close relatives, but a different family.