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Lord Vishnu Revealed Himself to King

The Lord Vishnu exposed himself to the king sathyavrata that he took this matsya avatar to protect the world and Vedas from the large deluge / flood which is going to happen on the seventh day from that day. The Lord asked for the King to gather some herbs, seeds, seven saints along with vasuki and other living animals to be set in a boat. The boat is to be appended to the fish's horns. The Lord said that He as a fish would lead them amid the downpour.

At that point to renovate the Vedas, Matsya flied into the sea to destroy the demon Hayagriva. An incensed fight followed between Lord Vishnu and evil spirit Hayagriva for seven days, in which Hayagriva was beaten and killed. Lord Vishnu restored and brought back the Vedas to brahma.

Matsya Avatar Story

Matsya Avatara is first among the dasavatara is to show how Lord Vishnu incarnated himself on this universe as a fish just to spare the universe from the demon Hayagriva and gave back the Vedas to Brahma.

The Fish and King Satyavaratha/Manu

Matsya avatar is portrayed to have first to save the person sathyavrata from the great surge/ flood. Sathyavrata is the king who is a great devotee of Lord Vishnu; he was around the river for his morning supplications to the god Vishnu. His morning prayer to lord Vishnu was his day by day. After he lifted himself up off the grass, Satyavrata headed toward the stream to wash his hands and clean himself. He found the small fish while washing his hands in the river.

The fish asked for him to safeguard it. The King consented to offer haven to the fish and kept it in a water jug. The King had not understood that the fish was none other than the Lord Vishnu. The godly Fish now needed to uncover its holiness to the King. Rapidly, the fish developed in size so it must be expelled from the container and put in a bigger waterway. The King then put the fish in a well. Again the fish exposed itself to bigger to possess the entire well. The King now set it in a lake, yet the lake soon turned out to be tiny. The King replaced the fish to the Sea if all else fails. The godly Fish extended to involve the entire ocean.

Do's

Must worship Lord Vishnu
Chant Lord Vishnu Mantras while doing puja
Observe fasting on the day of Matya Jayanti
Offer food to poor peoples.
Visit nearby Lord Vishnu Temples.

Don't s:

Should avoid eating Non-veg on this auspicious day.
Should not involve in any wrong doings.
Drinking alcohol or smoking is strictly avoidable while observing fasting.