Christian symbolism
The fish was the most important symbol to early Christians. The symbolic fish was familiar to Christians from the earliest times. It can be seen in Roman monuments such as the Capella Greca and the Sacrament Chapels of the catacomb of St Callistus.  The fish was used as a Christian symbol in the first decades of the 2nd century. The symbol may come from the miracle Jesus is said to have performed by multiplying loaves of bread and fishes on the shore of the Sea of Galilee. Its popularity is thought to mainly come from an acrostic made of the first letters of five Greek words Iesous CHristos THeou Yios Soter. These form the Greek word Ichthys which means fish. Iesous Christos Theou Yios Soter translates as Jesus Christ, Son of God, Saviour.