In blue sea, in white foam

The boy and his grandfather, while fishing at sea, pull a sealed jug from their net, from which the king of the sea emerges. He forcibly takes the boy to the underwater kingdom to make him an apprentice and heir, marrying his daughter. The boy does not want to spend the rest of his life sinking ships with people, even though it promises him riches. Pretending to agree to the sea king's proposal, he tricks him into climbing back into the jug, after which he ends up back in the boat with his grandfather and throws the jug back into the sea. The jug ends up in an aquarium on the seabed and stays there.