Michauxii;
How about a piece of 4" PVC to sleeve over the 2". Put a couple bolts through the 4" pipe so it sets where you want it on top of the 2-inch. I'd sleeve it a couple feet over the 2" and this should preclude any debris from getting into your pipe. Plus, this draws subsurface water out instead of the oxygenated surface water. (obviously, extend the 4" pipe above surface level of water). I wouldn't think you'd have a problem with minnows getting between the pipes and into your pump.

Joe