In order to fish you will need a fishing pole and some bait. Fishing poles can be purchased, or you might find someone to make you one from dowel, string, a fishing weight and a fish hook. For bait, any raw meat will do or some people like to use herring. You can buy bait at the dock in Tobermore. To put the bait on your hook, use 'bait hook' or 'bait pole'.
In the hexes, you may stand in a hex next to a river, lake or ocean. Then use 'fish dir' where dir is the direction of the body of water. On a dock, or the bridge in Eristan, or in a room with a pond, you may use 'fish out'.
Once you start fishing, you'll continue to fish until you hook something. If, for any reason, you wish to stop fishing, use 'stop fishing'. If you think you might have lost your bait, you can use 'check bait' to see. Different fishes live in different waters. There's a difference between freshwater (rivers and lakes) and saltwater (oceans). There's also a difference between temperate (northern) and tropical (southern) waters.
In general, freshwater fish are easier than saltwater fish and northern fish are easier than southern fish. So, one should start out in northern freshwater -- the river by Eristan or the bridge is a good place to start. Then move to the dock at Tobermore, then go south to Tirachi and the dock at Gilmore.
Once you've caught a fish, it will flop around for a bit and die. You will then want to butcher it to get the meat, either to re-use it as bait or for food. There are some good fish recipes out there.
Most of all, fishing is relaxing. If that House war is getting you down, there's nothing like going off with some herring and a fishing pole and dropping a line in the water to cheer you up!
Happy Fishing!
See Also: help lobster fishing, help net fishing