By the time he turned around and was getting ready to perform his morning puja, he once again heard the fish address him “Please help me, this vessel is not big enough for me.” Surprised, when Manu turned around, he saw that the fish had grown up to three hands in length. He then transferred the fish to another bigger vessel, and when he saw that the fish outgrew this vessel as well, he transferred it to a well. By now he was sure that this was no ordinary fish and so when the fish outgrew the well, and he had to transfer it to a pond and then to the river, he addressed it thus.
“Who are you? I have never seen or heard of such wonders in my life. Are you a demon or a rakshasa deluding me with these illusions and shape-changing? No, I don’t think you mean any harm to me. Perhaps you are Narayana himself. Please tell me the truth and put my mind at peace.”
The fish then smiled at Manu and told him that he was indeed Lord Vishnu. Overcome with joy and emotion, Manu prostrated himself before the fish and with teary eyes expressed his gratitude “O Lord, all my prayers have been answered. I am indeed blessed to have seen you with my own eyes. Please tell me what it is that I can do for you.”
Vishnu then told Manu that the whole world would soon be flooded with water and tasked him with building a ship big enough to carry one pair of every living being on earth. As soon as Manu started building the ship as per the instructions, Vishnu disappeared with the instructions that he would appear at an appropriate time when the earth was flooded and that the ship would then prove to be of use.
After Manu finished building the ship, Vishnu appeared in the shape of the same fish, except that this time he was gigantic and many more times larger than the last time that Manu had seen him. He also had a horn on his head, which was unusual for any fish. Soon, there were torrential rains all over the world which flooded the earth.
Speaking loudly over the roar of the rain and the lashing floods, Vishnu instructed Manu to herd together one pair of all living beings on earth on the ship. He then instructed Manu to use his celestial snake Vasuki as a rope and tie it to the horn on his head. Vishnu then, in the form of the Matsya, guided the boat through the choppy flood waters and led the same through the pralaya (destruction) that was unfolding at that point in time. Thus, Manu’s boon which had been granted to him by Lord Brahma was fulfilled to fruition; he ended up being the one person who saved the world from pralaya.
The above in a nutshell ends the popular depiction of the Matsya avatar of Lord Vishnu. However, sacred texts which deal with this incident go on to depict the conversation that Manu and the Matsya had when the fish was leading them through the choppy waters. This conversation forms the crux of what is termed the Matsya Purana, which forms an integral part of the Vishnu Purana.
The Matsya Purana among other things deals with various stories starting with the Creation and going on to talk about the various royal families, the duties of a householder, the story of Shiva, and various other miscellaneous stories as well.
I will try and publish posts on some of these stories from the Matsya Purana from time to time after having covered the rest of the avatars of Lord Vishnu first.