I have a small pond - less than 1/4th acre - that I raise fat head minnows in. The number of small snails has been steadily increasing until now there are thousands of them. With them came the little yellow worm that spends part of its lifecycle in the flesh of fish. Is there a natural control for these snails?

Redear Sunfish or Pumpkinseeds (which might do better for you if you are in Northern PA at high elevation) will love to eat your snails.

When big enough, they will also eat some Fatheads. But they aren't too prolific at spawning, and could be controlled fairly well by angling.

If you could get single sex Redears (adults can be sexed fairly easily), you wouldn't have to worry about reproduction.

Thanks for the info.