Scroll across the top of the menu...for 'View' I think it is.... then down to Fish ID right arrow and you can change the 'sensitivity' of the Fish ID.....run it over to a much higher number.....or Max...
You should see them then...
No, FishID and its sensitivity setting is in the SONAR main menu.
FishID has nothing to do with arches.
ALL LCR units will display an arch for subjects in the water column if the boat speed and screen scroll speed are set so it can.
It is entirely a result and time and distance of a subject within the sonar pulse.
For a cartoon example of how arches are formed, go to the Lowrance website and watch the sonar tutorial.