He found a small fish in his hands, along with the water knowing that a fish is happiest in the water; he threw it back into the river. The fish spoke to him in a human voice and told him that it would rather stay with him because it was afraid that the big fish would eat it up in the river. It would like the king to take it with him.
So the king put it in his kamandal and took it home. The king put her in a bowl of water but the next day he saw that the fish had grown bigger. On seeing Satyavrata it asked for more space. Satyavrata took it to a nearby pond and deposited it there. Next day the fish had grown even bigger than before and could not swim in the pond freely.
The king found a larger pond for it but the same thing again happened: it grew bigger until the king decided to throw it back in the sea. The fish tried to argue with him, but Satyavrata told it that he was quite sure that it was no ordinary fish, and that it had some purpose behind all this ‘leela’.
The fish having tested the king was now convinced that Satyavrata was a noble and kind man and the right one for it to disclose its true identity, and the purpose for its birth. The fish told Satyavrata that it was really the incarnation of Vishnu and had to take this form of life because pralay was about to deluge the world and water would engulf everything. But the eternal rishis, herbs and seeds had to be saved for the next Manvantra.
It warned Satyavrata that only seven days were left, and he will see great clouds in the horizon and the rains will fall in torrents and water will be everywhere. Narayan had chosen Satyavrata for the purpose of transferring the very essential items for the next “Creation”. It also told Satyavrata that a boat will automatically come to him before everything is completely submerged, and he should by then have collected all the immortal rishis, plants and seeds, etc. and get into the boat alongwith these men and things.
The fish which was Narayan himself will come to save them. The fish will have two horns, and Satyavrata with the consent of ‘Vasuki’ the serpent should use him as a rope and tie the boat to the horns of the huge fish.
The boat will be tossed hither and thither, but he should not be afraid as the fish will guide him across to the next ‘Manvantra’. Thus the first avtar of Narayan came in the form of a fish. It is in tune with the Darwin theory of evolution although woven around a story to keep everyone interested in listening to it.
This story is very akin to the story of the “Noahs’ Arc” and seems to have its origin with the Aryans before they spread out from the Central Asia into the rest of the world.