dimples on the surface

What are the small dimples the appear on the water surface. I thought they were minnows but can not see them.

Larvae of some sort??

Could well be fall water turnover.

In most cases you will periodically see small bubbles coming from the bottom all the way to the surface.

i would say rain, especially today.

I thought it was shad feeding-

I was fishing a small lake today and every time my lure hit the water the surface would erupt with small fish. I've had this happen before with shad, but not on the scale I experienced today. A few times a larger fish would boil, so I know something was feeding on them but I never got a strike. I was casting from shore so I couldn't tell much about the fish except they seemed to be very small, probably minnows or baby shad.