When against these creatures in the night time, you can use the fire from a Wooden Torch to scare them off.
If a Fen Stalker sees a frog they shall try to mimic them by jumping up and down as a sign of friendship. Furthermore, if it sees a frog getting attacked it will jump to its aid.
Fen Stalkers can be baited with any type of Fish (So far it as been only shown to work with Raw Fish). When a fish is placed before them they will crawl up and begin consuming the fish. This makes him docile until he has finished the fish, allowing a safe path.