(Temporary note: different types of water, fresh or salt, may determine what types of fish are caught, or if you even can fish. If anyone can confirm or deny this, please edit the page or comment below. This information is also from a source a little over a year old, it may have changed.)
Fishing requires a fishing rod and a body of water. First, cast your line into the water. Wait until "Oh, a bite!" appears. Begin reeling in your line. The rod will bend based on the amount of resistance the fish is giving. If "Your line is about to snap" appears, make sure to give the fish some slack. Alternate reeling and giving slack until the fish tires out and you'll be able to reel it in the rest of the way.