ICHTHUS

The word Greek for fish is ICHTHUS and its five letters form the Greek acronym with the phrase:
Iesus Christus Theou Yicus Soter, that wants to say:
Jesus Christ son of Rescuer God.

The drawing of a fish became symbol of the first Christians who, in persecution times, used it as private signal of the faith. Where, a Christian to identify if to one another person were brother in the faith, drew an arc in the sand. If to another person it was Christian, in contrast drew the arc, thus forming, the drawing of a fish.

With passing of the years the figure of the fish associated then with the Christianity.