Mbh 3.186.2a

“Markandeya replied, ‘O king, O foremost of men, there was a powerful and great Rishi of the name of Manu. He was the son of Vivaswan and was equal unto Brahma in glory. And he far excelled his father and grandfather in strength, in power, in fortune, as also in religious austerities. And standing on one leg and with uplifted hand, that lord of men did severe penance in the jujube forest called Visala. And there with head downwards and with steadfast eyes he practised the rigid and severe penance for ten thousand years. And one day, whilst he was practising austerities there with wet clothes on and matted hair on head, a fish approaching the banks of the Chirini, addressed him thus, ‘Worshipful sir, I am a helpless little fish, I am afraid of the large ones; therefore, do thou, O great devotee, think it worth thy while to protect me from them; especially as this fixed custom is well established amongst us that the strong fish always preys upon the weak ones. Therefore do thou think it fit to save me from being drowned in this sea of terrors! I shall requite thee for thy good offices.’ On hearing these words from the fish, Vaivaswata Manu was overpowered with pity and he took out the fish from the water with his own hands. And the fish which had a body glistening like the rays of the moon when taken out of the water was put back in an earthen water-vessel. And thus reared that fish O king, grew up in size and Manu tended it carefully like a child. And after a long while, it became so large in size, that there was no room for it in that vessel. And then seeing Manu (one day), it again addressed these words to him, ‘Worshipful sir, do thou appoint some better habitation for me.’ And then the adorable Manu, the conqueror of hostile cities, took it out of that vessel and carried it to a large tank and placed it there. And there again the fish grew for many a long year.