Vitalik’s mother made him a present of a crucian carp and a small aquarium for it to live in. It was a beautiful little fish and Vitalik was very excited about it at first, he fed it and changed the water in the bowl regularly. But after a time he lost interest in it and sometimes he even forgot to feed it.

Vitalik had a kitten, too, called Murzik, a grey fluffy kitten with large green eyes. Murzik loved to watch the fish swimming about in its bowl. He could sit for hours beside the bowl with his eyes glued to the carp.

“You’d better keep an eye on Murzik,” Vitalik’s mother warned him. “He’ll eat up your fish one of these days.”
“No, he won’t,” said Vitalik. “I’ll see he doesn’t.”

One day when his mother was out, Vitalik’s friend Seryozha came to see him. When he saw the fish he said:
“That’s a nice little carp you’ve got there. I’ll give you a whistle for it if you like.”
“What do I need a whistle for?” said Vitalik. “I think a fish is much better than a whistle.”
“No, it isn’t. You can blow on a whistle, but what can you do with a fish?”
“You can watch it swimming in its bowl. And that’s more fun than blowing a whistle.”

“Rats,” said Seryozha. “Besides, the cat can gobble up your fish any time and then you won’t have a whistle or a fish either. But the cat won’t eat a whistle, because it’s made of iron.”
“Mummy doesn’t like me to swap things. She’ll buy me a whistle if I want one.”

“She’d never get one like this,” said Seryozha. “You can’t buy them in the shops. This is a real militiaman’s whistle. When I go outside in our yard and whistle everyone thinks it’s the militia.”
Seryozha took a whistle out of his pocket and blew a piercing blast on it.
“Let me have a try,” begged Vitalik.
He took the whistle and blew on it. It responded with a loud trill. Vitalik was enchanted. He longed to own the whistle but at the same time he didn’t want to part with his fish.
“Where would you put the fish if I changed with you? You haven’t got an aquarium.”
“I’d put it in a jam jar. We have a big one at home.”
“All right, take it,” said Vitalik, finally giving in.
They had a hard time taking the fish ,out of the bowl. It kept slipping out of their hands. At last, after splashing water all over the floor, Seryozha managed to catch it, wetting his sleeves up to the elbow in the process.
“I’ve got him!” he shouted. “Quick, bring me a glass of water.”

Vitalik brought a mug full of water and Seryozha dropped the fish into it. Then the two friends went to Seryozha’s place. The jam jar turned out to be not quite so big as Seryozha had said, and the fish had much less room than in its bowl. The boys stood watching it swimming back and forth in the jar. Seryozha was very pleased, but Vitalik felt a little sad. He was sorry he had given away his fish, and what is most important, he was afraid to tell his mother that he had exchanged it for a whistle.