Near lakes, you will see a wooden structure with water vibrations in front of it. These locations allow fishing if you have a fishing rod, which is obtained in one of the game's mandatory quests. When you fish, you either will catch a fish or a Lost and Found item, this one being a requirements for other achievement. Just catch a few fish—around 10—for the achievement to pop up. Catching fish restores some of your health, and you can give your leftovers to the container next to the black cat in the cabin. Good luck!