What is the meaning of the title of the book Big Fish?

It is a joke among fishermen that so many in their ranks exaggerate about the size of the "big fish" they caught. As they tell the story, the fish in question may be 40 inches long, then 45 at the next re-telling, then 50 inches. The novel is About a Boy who questions the fantastic stories his father told him, figuring them to be "big fish," or exaggerated, stories.