There is a lot of foreshadowing in Big Fish. One example of foreshadowing is the fact that he turns into a fish. The foreshadowing of this includes events like
Him needing water and being in the bath tub. Another example of foreshadowing is him telling the young girl in the town that he'd come back. A third example of foreshadowing is when the mother says," not all of your fathers stories are complete fabrications."
Big Fish also contains loads of flashbacks. All of the stories about Ed's history are flashbacks.
The suspense of the movie comes from not knowing if the stories are true or not.
The ending wasn't that surprising because of the foreshadowing of the fish. The most surprising thing was that the stories weren't completely true. The ending shows that it doesn't matter if a story is possible but if it was a good story. The resolution is that his stories are somewhat true.