Balloon fish
There are many kinds of fish that have an unusual way of protecting
themselves when they’re frightened or in danger. They swell up like a
balloon!
Many of these fish belong to a family of fish known as puffers, because
of the way they puff themselves up. There are many different kinds of
puffers, from little ones only a bit more than two inches (about 6
centimeters) to some 27 inches (90 cm) long.
All puffers have a kind of stretchable sack attached to the stomach.
They fill up the sack by gulping water rapidly. This makes a puffer
swell to twice its regular size. And while it is swollen, none but the
very largest fish can
puffer
Porcupine fish have sharp stickers. Most of the time the stickers lie
flat. These fish can puff themselves up so that they become spiky
balls.
swallow it. Swelling up keeps a puffer from getting eaten. If you pull a
puffer out of the water, it will gulp air to make itself swell up.
Another kind of fish that can blow itself up is the porcupine fish. A
porcupine fish has several hundred sharp stickers, or spines, all over
its body. The spines lie flat while the fish is swimming about. But when
it puffs itself up, the pointed spines lift up and stick straight out.
It would be a foolish fish indeed that would try to swallow such a large
spiky mouthful. Yet some sharks have been seen to swallow swollen
porcupine fish. What happened to the sharks isn’t known!
