[Knowledge Expander!] A Three-Choice Quiz about Fish for Elementary School Students

To intimidate the enemy

The pufferfish, with its adorably round, puffed-up look, has a special sac inside its body for inflating. When it senses danger, it takes in water or air to make itself larger and show this to its opponent. It can actually inflate by taking in more than twice its own body volume in water!

Because I'm always full

Unlike in the wild, sharks kept in aquariums are carefully managed so they don’t go hungry; they’re fed at feeding times until they’re full. Since their stomachs are full, they have no need to attack other fish.

whale shark

A whale shark swimming leisurely through the sea—individuals up to about 18 meters in length and weighing around 20 tons have been recorded. Although we often think of whales as very large, they are mammals, not fish.

scale (as on a fish or reptile)

Not only scales, but also the ear stones (otoliths) inside the ears and the vertebrae can be used to determine age. Like tree rings, they have growth lines, and the number of these lines is counted to make the determination. There are also ways to examine the age of fish you’ve eaten at home using a microscope and other tools.

to lure in the bait

In the pitch-dark deep sea, the small lights swaying gently look like tiny fish fluttering about, and the anglerfish eats the fish that are drawn to them. In fact, only the female’s lure glows; the male stays near the female and snatches food from the side.

Indo-Pacific sailfish

Named for its dorsal fin resembling the plant 'bashō' (banana plant), the sailfish, which reaches about 3 meters in length, can swim at speeds of over 100 km/h. It’s said that this incredible speed can sometimes cause it to injure itself.

sturgeon

Caviar is a delicacy made from salted sturgeon roe, also known as the “black jewel.” People often think sturgeon are a type of shark, but in fact they are not sharks; they are cartilaginous fish and ancient species that have existed for 300 million years.