Per this article key factors in a successful pond with crappie is the water clarity needs to be 24" the majority of the time so the bass can see to eat crappie, the pond needs to have rooted underwater plants so young bass can escape the crappie, and some sort of slot limit on bass:

https://mdc.mo.gov/property/pond-stream-care/ponds-fish-frog-management/crappie-small-ponds


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