Rosy spawn

[HARO]

I put about 40 Rosies in the pond after it was finished (late summer or early fall). Nothing was done to de-ice it that winter, and it froze to within an inch or two of the bottom. Surprizingly, most survived, and by early summer there were around 2,000 small Rosies in that pond! However, once goldfish were added the Rosy population rapidly declined, and by the following spring they were all gone. Predation? Competition for food? Who knows?
John