Put surface clutter on low, noise rejection on low. Check your transducer and make sure it is level.
Also, you will only see arches if the fish are directly under the cone angle and not moving. Fish on the edge of the cone angle may appear as dots. Zig zag that area and you should be able to get a better image of them once you are directly over them.
I prefer to see streaks or lines, those fish are actively feeding. Hope this helps.