Medan Journal (Day 4): The Boy and the Goldfish

The Goldfish, A Sacred Symbol of Danau Toba

Once upon a time, there was a boy. He loved fishing very much. One day, he caught a goldfish and when we wanted to cut it up, the fish spoke. It turned out that the goldfish was a goddess.

“O Please young lad. Don't kill me. In return, I'll be your wife,” she plead.
The boy agreed. The goldfish turned into a beautiful young lady and they got married. But the lady gave him one condition - they must never tell their children that she is from a fish descendant. 

Time passed. 

Soon, they were blessed with a beautiful child. He was madly obsessed with fish. Every day, on his way to deliver lunch to his father at his workplace, he would stop by the river and played with the fish. He would play with them for hours.

This occurred very frequently that soon afterwards it caused a bit of a problem. His father got impatience and angry. One day, he asked the kid, "Why are you always late? I'm starving you know!"

The child then explained what happened. The father got angry and cursed the boy.
He said: “Memang dasar anak ikan!” which can be loosely translated as “Truly, you are a child of the fish!”

The boy got upset and went home to his mother. The kid asked what did his father meant by "a child of the fish"? 

"Mother, is it true that I'm from a descendent of the fish?" He asked.

The mother got angry for her husband had broke his promise. 

In her rage, she summoned strong wind and heavy rain that continued for a long time that the land they lived in was heavily flooded.

And thus, Lake Toba was born. 

The legend was passed on from a generation to another and until today, the people around here would honour the goldfish, which can be found in abundant in Lake Toba, and would refrain from eating them.
Or...
You always can go with the volcano lake theory. :)