Matsya Avatara (मत्स्यावतारः)

Once, Vaivasvata Manu was practising penance for gaining objects of enjoyment and for release from mundane existence. When he was offering water as a ritual in the river Krtamala, a small fish came from the waters into his folded palms. As he was about to throw it back into the waters, the fish requested him not to do so as there was fear of crocodiles in the waters. Having heard this, Manu put the fish into a vessel. When it grew in size, the fish requested for a bigger vessel. But soon, it outgrew the big vessel also and was put into a tank. And eventually, as it grew as big as the tank, Manu released the fish into the ocean and in a moment the fish grew in size extending to one lakh yojanas. Manu then realised the fish to be none other than Sri Vishnu and at his behest the lord in the form of a fish said, “I have manifested for the protection of this universe and for the destruction of the wicked. On the seventh day, the ocean would flood the earth. Having collected the seeds of creation in the boat that would approach you, you should spend a night of Brahma (equal to 1000 mortal years) on it being encircled by the saptarshis. And bind the boat to my horn with the big serpent (as the rope). Saying thus, the fish disappeared. As the appointed hour approached and the ocean began to swell, Manu boarded the boat as instructed. The fish now appeared with a single golden horn of one million yojanas in length. And Manu tied the boat to its horn. Manu praised the lord in the form of a fish with adorations. And it was at this hour that the Matsya Purana, capable of destroying papas, was revealed by the lord in the form of a fish to Manu. This story of the Matsya Avatara occurs in the second chapter of the Agni Purana.