The ten incarnations of Vishnu are a recurrent theme in Vedic history. Vishnu exists outside the material realm as the creator, and he exists within every being as the Supersoul. He also enters this world as avatar, 'one who descends', to restore balance whenever his presence is needed. His descent is described by Krishna:
"Whenever there is a decline of religion, and a rise of irreligion, I incarnate myself. To protect the good, to destroy the wicked, and to re-establish religious principles, I appear in every age."
There are said to be more incarnations of Godhead than there are waves in the ocean. It is also said that Vishnu incarnates in all species of life. The ten avatars of Vishnu are of particular interest because He takes progressively more developed forms, from fish, tortoise and boar to half-animal, half-man, and finally human form. That God should incarnate as an animal, even a supernatural one, shows that animals have an important role to play in God's eyes. They are not simply dumb beasts, or 'livestock' meant for satisfying human needs and appetites. They are living expressions of the spirit and of the presence of God.
The First Incarnation
MATSYA - The Fish
All glories to you, O Lord of the universe, who took the form of a fish. When the sacred hymns of the Vedas were lost in the waters of universal devastation, you swam like a boat in that vast ocean to rescue them.
Once a King named Satyavrata was performing a sacred ceremony beside a river. While scooping water from the river he accidentally caught a tiny fish in the palm of his hand. The fish begged him not to throw it back into the river where it would be eaten by larger fish. The king felt sorry for the little fish and took it home to his palace where he put it in a small bowl. Next morning the fish had outgrown the bowl and begged the king to put it in something larger. The king then transferred it into a pond, but it very quickly outgrew that too, so he put it into a small lake. Within no time the fish had outgrown the lake and had to be put into the largest lake in the kingdom. Soon, however it had grown so big that even this was not large enough and the amazing fish had to be put in the ocean.
By this time the king concluded that the fish must be a divine appearance of God. He offered prayers and asked it why it had taken this form. Matsya, the fish incarnation of Vishnu, replied that in seven days a huge devastation would engulf the lower part of the universe. He told the king to call the seven great sages and gather samples of all the herbs and seeds and all kinds of living creatures. He promised that he would send a large boat to save them all. After that the king would fully understand who he was. Then he swam away.
As Matsya had predicted, huge clouds appeared from all directions and began pouring incessant water on land and sea. Soon the ocean overflowed onto the land. Then Satyavrata and all his companions saw a large mysterious boat floating towards them across the waves. Remembering the words of Matsya, Satyavrata led them aboard it and they found safety. Matsya, who by now was a golden fish of inconceivable size, then appeared in the ocean. Using the giant serpent Vasuki, they tied the boat to Matsya's horn and he towed it, full of all the different species of life, across the waters of devastation. For countless years darkness covered the worlds and together they wandered across the stormy wastes waiting for the waters to subside. During their journey Vishnu-Matsya instructed King Satyavrata and the sages in the spiritual knowledge of the Vedas.
It is said that whoever hears this story is delivered from the ocean of sinful life.