Well, this post is so old, you may have given up on any answer. I have raised goldfish since 1967, spawning them in ponds and aquariums. To get them to spawn, early in the season, increase their food. Then do a good partial water change. That will usually induce them to spawn. They begin spawning early in the morning, and while two or three are in the spawning chase, the rest will be following behind eating the eggs. Check the floating plants early...remove to a safe place to hatch. The eggs are about pin head size, and amber-ish in color. Be sure the water you transfer eggs to is aged...a light green algae color is best. But if you want to just raise them in the pond with the other fish, some should make it. Unless you have gambusia (mosquito fish) in the pond. They are very efficient baby fish eaters. I would never have them in a pond of mine, if I had goldfish in it....even if I didn't want goldfish babies. They multiply out of control. They are not very good at eating their own babies.

Generally speaking, goldfish will spawn more than once a season. A drop in temperature and fresh water will get them to spawn. Hope this helps.

They breed like crazy, are invasive, so please never release them into the wild. I have hundreds in my large pond and cant get rid of them!