What more is there to "fishing" than what you already know? Remember, Peter was a FISHERMAN. He KNEW everything there was to know about FISHING. Along comes Jesus who did not have the experience that Peter did, and yet in a moments time, there were more fish in the net than could be counted. Later, the miracle of fish took on an additional characteristic. The fish were counted totaling 153 fish.
One thing that you will not notice.... there is no explaination why the fish were counted in one place, and not counted in another place. The reason I say that you will NOT notice it is because it is a detail the is merely mentioned, and there is no explaination as to why it is mentioned. In fact, you may argue that it has no significance because if it is only merely mentioned, and God would have had Paul write a chapter in the Bible about it if it was significant. On the other hand, you may argue that it IS a significant detail because the mere mention of it makes it significant.
Jesus told Peter, James, and John that now they would be fishers of men. Jerome says there were 153 species of fish in the Sea of Galilee. I think since there was every species of fish in the net that that meant the disciples would go to every ethnos of man.