After encountering a particular type of creature, the character shouldn't have to make Fear checks every time he sees another one in that particular scenario. If the party clears out a dungeon full of zombies, for example, they should only have to roll the first time they encounter them–not in every room. The Game Master might require a roll if the heroes encounter zombies in a particularly different or frightening situation, however, such as if they fall into a pit full of the ravenous creatures.
Savage Worlds Deluxe Edition p. 98