Matsya flood myth

The myth of Matsya is about a king who, with his family, survive a “great flood”, along with the Seven Sages, the four Vedas, nine types of seeds, and various animals, with the aid of Lord Vishnu.

Shraddhadeva Manu
Shraddhadeva Manu (also known as Satyavrata, meaning "always truthful") is an antediluvian king of the before the Great Flood, according to Hindu tradition. Manu is said to be the son of (also known as Manuvaivasvata). Manu is forewarned of a coming "great flood" by the  of Vishnu. He saves humanity by heeding a warning from Vishnu, to seek protection on a "big boat" that is designed to carry his family and the to safety.

The puranas
In the Bhagavata and Matsya, Vishnu reveals himself and informs the king of a "great flood" where "earth, ether and heaven will be flooded by the all-devouring ocean; When the three worlds are submerged in the waters of annihilation." Vishnu sends a "big boat" to protect Manu's family, the saptarishi, nine types of seeds, and animals to repopulate the earth—after the deluge ends and the oceans and seas recede. In preparation for the coming flood, Vishnu appears as a "golden fish" having a horn by which the king fastens the "great serpent"  (who is used as a rope) from the horn to the boat. After the great flood, the boat perches on the top of the. Manu's family and the seven sages then repopulate the earth. Praise is given to Vishnu for having "returned the Vedic records that were stolen from the mouths of Lord Brahmâ who lay deep asleep in the waters of the flood.'"

Timescale
By reference of the time-lines given in the puranas, Manu's story is calculated to have occurred before 28 in the present, which is the 7th Manvantara. This amounts to 120 million years ago.