Matsya Jayanti is a Hindu festival that celebrates the birth anniversary of Lord Matsya, who is believed to be the first avatar of Lord Vishnu in the form of a fish. Lord Vishnu took this incarnation during the Satya Yuga, the first epoch of time, to save humanity and other living beings from a great deluge that threatened to destroy the world.

According to Hindu mythology, Lord Vishnu appeared as a one-horned fish to King Manu, who was performing a ritual on the banks of a river. The fish asked Manu to protect it from bigger fishes and promised to save him from an impending flood. Manu agreed and kept the fish in a jar, but it soon grew too big for it. He then transferred it to a bigger vessel, then a pond, then a lake and finally the ocean. The fish revealed itself as Lord Vishnu and instructed Manu to build a large boat and take along seeds of all plants and pairs of all animals. He also gave him a sacred thread tied with seven knots and told him to tie it around his wrist.

When the flood came, Manu boarded the boat with his family and other creatures. The fish appeared again with a horn on its head and told Manu to tie the boat to its horn using the sacred thread. The fish then towed the boat across the turbulent waters for seven days and nights until they reached Mount Meru, where he anchored it safely. The fish then told Manu that he was chosen as the progenitor of mankind for his piety and devotion. He also revealed that he had preserved the Vedas, which were stolen by a demon named Hayagriva, in his stomach during the flood. He then killed Hayagriva and restored the Vedas to Brahma, who created a new world order.

Matsya Jayanti is observed on Tritiya (third day) of Chaitra month (March-April) according to Hindu calendar. On this day, devotees worship Lord Vishnu’s Matsya avatar by offering prayers, fasting, chanting mantras and reading scriptures. They also donate food, clothes and money to Brahmins (priests) and poor people as an act of charity. Some people also observe partial fast by eating only fruits or milk products.

Matsya Jayanti is considered auspicious for starting new ventures or projects as it symbolizes new beginnings after destruction. It also reminds people of their duty towards nature and other living beings as well as their faith in God’s protection.