Legend of the River King GB

As a young boy, you must search out the fish called Guardian, the only fish in the river that can cure a disease caught by your sister, Teruyo. This mode combines RPG elements such as buying items, talking to the town's folk and searching the local river for the Guardian fish. The fishing element comes into play when you bait or lure fish at the river, in hopes to find a fish. (mobygames)