You don´t need to train it at all and still can catch most fish easily.

Use a boat and park next to fish, then just drop the line into the water from the boat. 1-3 meters is enough. You don´t need to cast far. Use three good stam foods and you won´t have any trouble. The trick is to cast as short as possible. Fish don´t care and still bite and you don´t have much to reel in.