It is clear that the golden carp in this excellent novel stands for a pagan religion, offering another possibility to make sense of our existence and another explanation for the world. When Samuel first tells Antonio about the golden carp in Chapter Nine, the way that the golden carp stands for an alternative belief to Christianity is obvious. Note how Samuel explains the existence of the golden carp:
"When the gods had turned the people into carp, the one kind god who loved the people grew very sad. The river was full of dangers to the new fish. So he went to the other gods and told them he chose to be turned into a carp and swim in teh river where he could take care of his people. The gods agreed. But because he was a god they made him very big and coloured him the colour of gold. And they made him the lord of all the waters of the valley."
Antonio is bemused by the idea of a "new god," which disturbs the beliefs of Antonio and makes him wonder about who Jesus was and if his mother was praying to "the wrong God." An important theme of this great novel is the way in which the clash of cultures is represented through the presentation of different belief systems and religions. Antonio is able to piece together his own identity by incorporating bits from both the pagan religion that the golden carp stands for, and Christianity.
The golden carp is another god that makes Tony doubt his own god that he has been taught to love and become a servant of him and he plans on becoming a priest.