This is a complete achievement walkthrough of The Fall on Xbox One. During this playthrough I unlock every achievement except for "Merciful" which is unlocked at the very end of the game. I explain how to get that achievement near the end.
Video Start Time - 34:18
This achievement is for killing the second fish after draining the water. After you activate the second panel in the bottom of the Labs area, the water will drain and the fish that was swimming around your feet will now be flopping on the ground. Simply aim and shoot the fish to unlock this achievement.