The story of Manu - Vaisvati.

Manu was a great king of risis, he was performing penance on one foot with his hands raised. He performed a rigorous Tapas on the banks of river.

Once reaching to the water in the banks, he saw a fish looking at him in great vain. The king asks, 

"Oh. Matsya! you look so beautiful with your blue skin. What is it that has been bothering you?"

The fish talks to the king "I am very young in this water living among beasts and bliss, So save me from the harm that can lurk on me." The king takes out the blue beautiful young fish out of the river and puts in to a small pond. The fish starts growing by days. The king looks at the growing fish & decides to accommodate a place for its size, he kept changing the place of fish from pond to a lake to a river to Ganga. Finally, when the fish became so big it couldn't fit in Ganga. King had to leave it in to the oceans. The big fish talks to the king "O! The great king of the earth. you are kind and beloved to me. You are very compassionate. I will tell you my purpose on this earth. This earth needs a purification of its sins and then when that happens you the just king of earth has to build an arc and unite the worthy 7 rishis of this earth and arrange necessaries for survival for a long time"

The great winds of rain flooded the earth & darkness spread fear. Manu and his 7 rishis entered the arc. They waited for the horned fish from the ocean and it came as promised and pulled the arc over
for days to come till the new sun raised.

When the new sun raised. The Horned fish leaves the arc to the shore, speaks so; "O! Manu this is the new world and now you have my blessings to create a new world and a just order of being on this earth" My time has come to leave and I shall come time and again in different forms to rinse this world of its sins and vulgarities.

- The story.