No question that the easiest, most complete fix would be to pump her dry and start ovr. If no one is going to manage the pond with any regularity [feed, monitor fish population etc]for a while, you could just stock forage fish, shiners and fatheads, and let them expand for a couple years, then introduce a limited number of predators and have a great run. You could also add the forage, then add a predator that won't reproduce [HSB] during the unmanaged phase.
If you don't want to drain-you could add a few flatheads. In a small pond with limited cover, they'll fix your crappie problem. Of course, then you'll have a flathead problem if you restock without draining, but at least that's a more interesting problem.
In any event, adding fatheads, shiners, or any other forage species to such an already unbalanced pond probably won't fix anything--just adding snacks, as FnC suggested.
