Fear in dogs can be shown in a number of ways. Most common is tail between the legs, ears back, shrinking posture, and trying to run away from the stimulus. Fear can lead to aggression if a dog is put under too much stress.
Check out the videos below to learn all about dog e-collar training. You'll not only learn about training your dog using an electronic collar; you'll also learn how training differs for dogs that are stable versus dogs that have behavior issues. Due to time constraints, there will only be videos and no short summary