My goldfish has outgrown his tank, and I wondered if he would survive in a pond... which is more like a lake... about the size of a football field. Once he goes in, there would be no way to get him back out for the winter. There are other fish in the pond, mainly trout, as well as frogs.

So is this pond a mud pond? I have not heard of goldfish being in mud pond. But I think they will be ok. My concern is with the trouts. They may harass the goldie. How big is your fish now?

My goldfish is about 6 inches long now. The pond does have a mud bottom and is about 12 feet deep in the middle. The ice can get about a foot thick in the winter. The trout must go to the bottom in the winter - I don't know what the frogs do. But they all come back in the spring. Will the harrassment take the form of killing?

I think goldie will be fine. However, that is a huge pond and I assume that since it has mud bottom, the water is not very clear. So you will not be able to see him/her afterwards. In any case, sounds like a better place to live than a small tank. Good luck.