In Tony's already confused world of magic versus religion, the Golden Carp signifies yet one more source for his doubts about Christianity. Cico introduces Tony to the Golden Carp, a pagan god who is a symbol of forgiveness, unlike the Christian God who Tony believes is cruel and unforgiving. The carp is beautiful and huge, a true source of awe. At the realization that, contrary to Christian belief, there are other gods, Tony begins to question who his mother is truly praying to- who is Jesus, who is the Virgen de Guadalupe?
Tony's doubts about Christianity further deepen when he makes his First Holy Communion, a religious rite of passage in Catholicism where children eat God's body in the form of a wafer. Antonio expects to hear the voice of God at the moment the takes the Eucharist into his body. He expects that this will be a monumental event and that everything will be clear to him after that. After nothing happens, Tony is utterly disappointed. He wonders why he can see the carp and not God.
The golden carp is like an allusion to the fish of Christianity blended with the ancient stories of the Native Americans. It's presence is powerful and the story behind it is similar to many myths, one of recreation and wanting to protect its people. The golden carp itself is beautiful, and Tony has been struck by it. That sudden "illumination of beauty and understanding flashed through [his] mind," but then he realized that "this is what [he] had expected God to do at his first holy communion" (119). Is this sin? But there is a presence in the river that Antonio feels. What are you supposed to believe in? Can you believe in God, but in nature as well? Where is God when you need him?
The golden carp is a physical manifestation of the personal struggle Antonio has to make about his faith.