If the pond does get out of balance and overpopulated with small crappie, stock 30-50 adult largemouth bass (10 to 12 inches long) per acre.
Another good strategy is to not bass fish close to the banks in the spring and early summer. The male bass do a good job of protecting their fry and smaller fingerlings. If you catch the male LMB, most of his fry will probably be wiped out.