Big Fish is a novel about a father and son, Edward and William Bloom. It is the son's recollection of the stories his father told him. Edward is on a deathbed. He has always told his son fantastic stories about his life, so he decides to so at that moment as well. The novel has previously told of Edward’s growing up, his ability to communicate with animals, and his unnatural growth, making William believe that he is a big fish.
One of the stories about Edward’s life include him meeting Karl the Giant, a giant boy he advised to become a farmer to satiate his enormous appetite. He recalls a flood that destroyed Karl’s crops and half of the Ashland, and his diving into the water to see people continuing to live their lives in water. Another story is about Edward visiting a place with no name, where people are not moving but standing like statues. A dog approaches Edward there and eventually rescues him from becoming a part of the town with no name.
There is also a story about Edward in college and how he rescued an old lady’s glass eye from a group of ruffians, after which the narration jumps to the present with William of Edward’s deathbed, inquiring about God, and being frustrated with Edward’s inability to be sincere with him, even for once.
The narration jumps back into retelling Edward’s life, and how he met William’s mother, Sandra, and won her over. It continues with recollection of the various jobs Edward had and his time as a sailor, when he almost drowned, but was rescued by the river girl. Edward’s death is near and William starts recollection of his childhood, how Edward was a scarce but meaningful presence in his life, and concludes that Edward’s greatest gift is making people laugh.
On his deathbed, Edward has a dream where he is visited by all the people he helped and made laugh. The narration jumps back into the past, and tells the story of how Edward and Sandra almost had a divorce, and how Edward had an affair just before he discovered he has cancer. He returns home and visits the pool daily, which becomes more swampy the more his health deteriorates.
The novel end with Edward being in a hospital. William decides to tell one of his jokes back at him, about a man in a too big of a suit, and Edward closes his eyes. William decides to kidnap his father out of the hospital and brings him to a river, where he transforms into a fish and swims away.
