大唐西域記 7.4.2

7.4.2

From this going west along the side of the river, we find a stûpa about 30 feet high. To the south of it is a stretch of deep water. The great merciful Lord of the World converted here some fishermen. In days long past, when Buddha was living, there were 500 fishermen who joined in partnership to fish for and catch the finny tribes, whereupon they entangled in the river stream a great fish with eighteen heads; each head had two eyes. The fishermen desired to kill it, but Tathâgata being then in the country of Vais'âli, with his divine sight saw what was going on, and raising within him a compassionate heart, he used this opportunity as a means for converting and directing (men). Accordingly, in order to open their minds, he said to the great congregation, "In the Vrijji country there is a great fish; I wish to guide it (into the right way), in order to enlighten the fishermen; you therefore should embrace this opportunity."