Fish are everywhere. Past the moss, the temperature drops to 65. There's a breathtaking thermocline at around 34 feet, with the temperature below at 54 degrees. Visibility is quite good for Utah at 20 to 30 feet. Picture by Bruce Argyle, Nikonos V 20 mm lens.
Visibility is best in shallower water.
At around 30 feet, the light no longer supports plant growth, and the bottom turns sandy and uninteresting. That is, unless you like finding a hundred years' worth of fish traps, lures, bottles, golf balls, and sunglasses. Mid-day darkness occurs at around 60 feet. Your limit is two per day. For perch, you'll run into them anytime.