This post is asking several questions, and the third question is best left up to an individual reader. It most definitely lends itself toward an argumentative essay that attempts to argue how Edward did (or didn't) become the "big fish" that he was always striving to become.

The title of this story is quite appropriate, and the title shouldn't come across as an odd title as readers move through the story and get to know Edward. Edward openly admits that he wanted to be a "big fish."

I wanted to be a great man .… I thought it was my destiny. A big fish in a big pond—that’s what I wanted.

As odd as the story can be at times, and considering how important water is throughout the text, I want to make it clear that Edward does not literally mean that he wants to turn into a big fish. Edward is more or less saying that he wants to grow into a great person that does great things; however, he is also averse to the idea of being the "big fish" in a small pond.

Edward wants to grow into the metaphorical big fish, and he knows that in order to do that, he must live in a "big pond." The world he lives in and the world that he participates in needs to match his big-fish desires. He wants to live big and grand in order to be big and grand. This causes him to be restless and always looking for the next adventure.