Why is the golden carp bad luck?

In the novel "Bless Me, Ultima" by Rudolfo Anaya, the golden carp symbolizes a conflict between traditional beliefs and Catholicism. It is considered bad luck because it represents a pagan deity that rivals the Christian faith, leading to a sense of guilt and fear among those who believe in it. The protagonist, Antonio, struggles with these conflicting beliefs, highlighting the tension between cultural heritage and religious doctrine. The golden carp ultimately challenges the characters to confront their values and beliefs.