Matsya (Fish in Sanskrit) was the first Avatar (the material appearance or incarnation of a deity on earth) of Vishnu in Hindu mythology. Vishnu, the Preserver, along with Brahma, the Creator and Shiva, the Destroyer, form the holy trinity in Hinduism known as the Trimurti. He is the guardian of men (Narayana) and protector of the order of things (dharma). Vishnu as Matsya is generally represented with the torso of a man and the lower part of a fish with golden scales, with either 2 or four arms, and conferring a boom (varada mudra).

He appears in the hindu flood myth, when the Gods would send a huge deluge to prepare the world for renovation. Manu, the sage, was bathing in a river when a small fish came into his hands pleading him to keep it safe. Manu kept the fish in a small bowl but the fish kept growing bigger and bigger overnight and had to be transferred to a jar, then to a lake and finally to the sea. The fish then revealed himself to be Vishnu and made a prophecy that in seven days the whole world would be flooded and instructed Manu on how to build an ark and fill it with pairs of all the creatures of the world, all medicinal herbs, all the varieties of seeds, and go accompanied by the seven saints. Then he tied himself to Manu’s ark using the giant serpent Vasuki as a rope and protected them from the storm and the floods. Manu asked Vishnu why mankind had to meet such fate to which he answered that he was the most moral man alive and that he would be the father of the future generations of men.

During the flood, Matsya recovered the four Vedas (the most ancient Hindu scriptures) that were stolen during the creation and returned them to Brahma. When the storms ended and the water subsided, Matsya left Manu and the others at the Himalayas, where they could begin human civilization again.