Italians eat fish on Christmas Eve because their tradition does not allow them to eat meat on that day. Commonly, they eat seven fishes to represent the seven sacraments.
The number of fish that people eat during Christmas Eve varies from one family to another. In the past, people only used to eat seven fish. Some families eat three to represent The Holy Trinity and The Three Wise Men. Some eat 13 fish to portray the 12 disciples and Jesus. Others eat 11 fish, excluding Jesus and Judas Iscariot. Italians eat different types of fish during the Eve, including lobsters, baccala, clamps, oysters and pupa among others.