Data gathered during two summers from five ponds at the Wolf Lake Hatchery near Kalamazoo, Michigan, showed little correlation between the rate of survival and the intensity of stocking bluegill yolk fry. Ponds stocked at rates that ranged from 2,500 to 323,000 yolk fry per acre were drained at the end of the first summer, the first winter, and the second summer. Not more than 40 percent of the fry stocked in the spring survived the first summer in any pond. By the end of the second summer as few as 1 percent and not more than 20 percent of the original stock remained. Fish that were stocked at lesser intensities grew faster than those stocked more heavily. Competition from Iowa darters apparently seriously impaired the survival of bluegill yolk fry in one pond during the first summer. In another pond green sunfish, that entered as young of the year through the water supply during the first summer, became dominant over the bluegills in number and total weight by the end of the second summer. Under the most favorable conditions for growth (little competition and ample food) bluegill yolk fry grew so rapidly that they spawned when 12 months old and reached an average total length of 6 inches in 17 months.