no it won't scare the fish... that is the actual sonar being sent out and the tick you hear is the return or echo you hear coming back to the transducer
You can hear it because it's not in the water - that's how you know it's working!
If you can hear it in the water, it's still fine. What you are hearing is the return of the sonar. Water is great at sound waves, but it generally muffles it a little bit. The closer you are to bottom, the more clicking you will hear, and the deeper you are, the less returns or echos you will hear.
You can try to turn down your ping speed or sensitivity... but it's workin just fine