Also known as Black-spotted Pufferfish, the Dog-faced Pufferfish got its name from its short, dog-like snout.
When stressed or threatened, it uses its highly elastic stomach and the ability to quickly ingest huge amounts of water (and sometimes air) to inflate itself into a ‘balloon’ several times its usual size to deter potential predators.
Here’s what else you probably don’t know about this quirky swimmer.
1. Two layers of skin
To facilitate its puffing up, the Dog-faced Pufferfish has 2 layers of strong, elastic skin. The inner layer is pleated like a Scotsman’s kilt. When the fish inflates, the skin extends and stiffens. When it deflates, the pleats return to a ‘loose, dangly’ state. Without a second layer of skin to cover it up, the Dog-faced Pufferfish would look like a swimming raisin, with the dangly skin causing serious drag as it swims.
With a smooth elastic outer layer, its body becomes streamlined to facilitate better swimming.
2. No scales
Unlike most fish, the Dog-faced Pufferfish has a rough, scale-less skin.
3. No pelvic fin
This fish has neither pelvic fin (paired fins on the bottom side) nor lateral line. Their dorsal fin and anal fin are small, and are located at the end of the body.
4. Beak-like mouth
Its snout is short with four teeth that are fused together into a beak-like form. This ‘beak’ grows continually, which is why it feeds on hard invertebrates like crustaceans and mollusks, and sometimes stony corals to keep its beak from overgrowing its mouth.
5. Nostril-like gills
Its gills are not as pronounced as most fish. They look more like nostril openings near their pectoral fins.
6. Different colours
The Dog-faced Pufferfish comes in a number of different colors, peppered with small black dots. The most common ones are grey overall with a brown chin and white band just below the eyes. Less common are the lemon-colored ones that are mostly bright yellow with a gray back. On rare occasions, you will even find a Dog-face Pufferfish that is a light bluish grey overall or even black.
7. They’re poisonous
Almost all pufferfish contain tetrodotoxin, a substance that makes them foul tasting and often lethal to other fish. Tetrodotoxin is deadly to humans too, up to 1,200 times more poisonous than cyanide. In fact, there is enough toxin in one pufferfish to kill 30 adult humans. And there is no known antidote.