The fish as a Christian symbol is nearly as old as the Christian faith itself.
The Christian fish symbol can be seen in the past in art and architecture and today it endures on bumper stickers and business cards as a sign of Christian faith.
Why is the Fish a Christian Symbol?
The fish is thought to have been chosen by the early Christians for several reasons:
The Greek word for fish (ICHTUS), works as an acrostic for I = Jesus, C = Christ, TH = God's, U = Son, S = Savior (Also see Christian beliefs about Jesus Christ)
The fish would not be an obvious Christian symbol to persecutors; It is said that during the persecution of the early church, a Christian meeting someone new would draw a single arc in the sand. If the other person was a Christian, he or she would complete the drawing of a fish with a second arc. If the second person was not a Christian, the ambiguity of the half-symbol would not reveal the first person as a Christian. (Also see Christian history and Christian beliefs and Christian fast facts)
Jesus' ministry is associated with fish: he chose several fishermen to be his disciples and declared he would make them "fishers of men."
The fish is also a symbol of baptism, since a fish is at home in the water.
The second fish symbol (to the right) is the ICHTHUS fish, with the Greek word for fish written out to emphasize the symbolic acrostic described above.
Although the word looks like IXOYE, the letters are from the Greek alphabet, so the "I" is actually an iota, the "X" is actually a chi, the "O" is actually a theta, the "Y" is an upsilon, and the "E" or "C" at the end is a sigma.
Taking the first sound from each of these Greek letter names, we get the transliteration into our alphabet of ICHTHUS.
When Christians do not need to worry about persecution, the Christian fish symbol often has "Jesus" written inside or includes a cross symbol. And of course, there have been many spoofs and variations of the popular Christian symbol, such as the "Darwin fish" (with legs).