You have a problem with your unit. Bottom left says 3.6 ft, top middle says 3.9. Probably ought to have that checked out.
Must be running down an old pond dam or something. You're that shallow but the unit is only picking up the bottom for 20 feet or so to each side. That or your reflection on the screen is blocking it.
Oh, there's a butt load of fish in that area.
Angler you are correct. I was idling down a narrow canal about 40 feet wide.
What is it?
It was Lily Pads!
This test was just to keep you on your toes. Carry on.