“St Anthony being at one time at Rimini, where there were a great number of heretics, and wishing to lead them by the light of faith into the way of truth, preached to them for several days, and reasoned with them on the faith of Christ and on the Holy Scriptures. They not only resisted his words, but were hardened and obstinate, refusing to listen to him.
At last St Anthony, inspired by God, went down to the sea-shore, where the river runs into the sea, and having placed himself on a bank between the river and the sea, he began to speak to the fishes as if the Lord had sent him to preach to them, and said: “Listen to the word of God, O ye fishes of the sea and of the river, seeing that the faithless heretics refuse to do so.”
No sooner had he spoken these words than suddenly so great a multitude of fishes, both small and great, approached the bank on which he stood, that never before had so many been seen in the sea or the river. All kept their heads out of the water, and seemed to be looking attentively on St Anthony’s face; all were ranged in perfect order and most peacefully, the smaller ones in front near the bank, after them came those a little bigger, and last of all, were the water was deeper, the largest.”
From “The Little Flowers of St. Francis of Assisi” 1476 Read more at CCEL