I go against the consensus and say leave them. It is a small pond and you can fish out the few adults which will remain after a few years. Between YP and SMB I think the goldfish spawn will be pounded into oblivion. Even though subsequent generations will revert to a drab color, they are still slow enough to be eaten. The few large adults left after some years might still be red and nice to look at. I have seen two ponds over the years that started with only goldfish and other smaller minnows and sunfish and after bass were added, they were all but gone after three years. One pond was LMB which I know can handle larger meals but the other had only SMB added and same result eventually. Both of these ponds were around 1/4 to half acre and had tons of goldfish to start and were stunted. After 5 or so years there were just a few really big goldfish left like 15 inches long plus and we could catch them with dough balls or baby bluegill on the hooks.