Matsya
Matsya,the fish appeared in the Satyuga.The fish incarnation is the first incarnation of Lord Vishnu.Lord Vishnu took the form of fish to retreive the vedas from demon called Hayagriva,who stole them from Lord Brahma when he was a sleep.Without the vedas creation of the Universe could not take place.Hence Lord Vishnu killed Hayagriva and took back the vedas in order to create a new universe.He also saved his disciple Satyavrata and a flock of living beings(human beings,animals,birds and other living beings) from the flood that almost drenched the earth,so that the life cycle continued on the earth.
