Fishing is a new aspect of the new world. You can be any race, class, or profession to catch fish with a fishing rod. Only the fishing profession can prepare the caught fish.
To fish you must be near water and your character face the water. Assign your fishing rod to a your action bar. Use the fishing rod action to cast your line. Your float will be above the water as in the left side of the below image. When a fish is on your line, the float will go under the water as in the right side of the below image. When your float is under the water, use the fishing rod action again to reel in your line with your catch.

Your catches may involve rotten shoes, weeds, or fish. If you catch fish, your fishing skill ability will increase. As you advance fishing skill abilities, you will only increase your fishing ability by catching more prize worthy fish. The current fish catches are detail at the
gekkinfo fishing page.
Once you have caught a bunch of fish, you can use the fishing profession to prepare the fish. As you prepare fish, you will gain fishing profession experience. All the other fish you can sell to make a small profit.
Currently, prepared fish are only used by the cooking profession to make savory dishes.
At the time of this guide, neither reincarnation or reseting professions will reset your fishing ability.