suspended fish

[Barefoot]

you could always try to anchor up and fish under submersible lights. this will draw shad in which will then draw in fish.

you could drift minnow rigs or jigs at 20 ft.

you could troll with planer boards but you would need a kicker motor (or a crap ton of batteries) and an accurate speedometer (like a gps) to do any real good.

@ 20 ft, it could very well be trout that you are seeing.

[Shimano4Life]

You could also try to drift right over top of them and vertically jig a spoon or blade bait.