Colourful fish in a clear pond are an easy prey for herons. In spring herons are on the search for food for their young. During summertime, when the young herons will have fledged, they are standing themselves fishing on the waterside. In autumn the supply of food for herons is limited and pond fish are an easy prey then. Fish are the main feed of a heron. With his long bill he can also wound large specimen perilously. After a successful effort the heron will return until the pond has been fished out. The motion sensor of the Laser Guard will detect arriving intruders and has a range of about 12 meters at an angle of 100°. The operation is quite effective against herons by three methods: 1. Flashlight with variable frequency makes the environment unpleasantly restless. 2. Herons consider the green laser beams as dangerous moving obstacles. 3. The sound of a congener in distress, barking dogs and the frightening cry of a deadly arrow poison frog will scare off herons for good. This scaring method will last 60 seconds each time. The scared invaders will flee so that the fish in your pond will be safe again.