In the early years of Christianity, the fish became a symbol of Christ, of newly baptized Christians, and of the Eucharist. The symbol may be derived from the acrostic “Jesus Christ, Son of God, Savior,” taken from the letters of the Greek word for fish, ichthus.
Follow Me, and I will make you fishers of men. Matthew 4:19
He took the five loaves and the two fish, and looking up to heaven, He blessed and broke and gave the loaves to the disciples. Matthew 14:17
Let our seals be either a dove, a fish, or a ship scudding before the wind. . . . If there is anyone fishing, he will remember the apostle, and the children drawn out of the water. Clement of Alexandria (c. 195, E), 2.285, 286
We, little fishes, after the example of our fish, Jesus Christ, are born in water. Tertullian (c. 198, W), 3.669
[IN REFERENCE TO MATT. 17:24–27:] This coin was not in the house of Jesus. Rather, it was in the sea, in the mouth of a fish of the sea. In my opinion, the fish was benefited when it came up and was caught in the net of Peter, who became a fisher of men. For in that net was that which is figuratively called a fish. Origen (c. 245, E), 9.481