I have an outdoor pond that has 6 large (10+ inch nose to tail) goldfish in it. These are fish that were originally bought as pet store feeder-type fish, so they're nothing special. I have a webcam on the pond, and have observed that several of the fish keep chasing, crowding, and trying to bump into one of the other fish (which is distinctly colored, so I know it's the one that's being consistently targeted).
I am suspecting that this is a breeding behavior where the targeted one is likely female and is ready to lay eggs and the others are males, trying to squeeze eggs out of her by pushing against her in order to fertilize them. But this is just a guess, as I'm not a goldfish behavior expert. :-) We did have some in-pond births last year with these same fish, so I know that there are both males and females in the pond.
So is this expected breeding behavior, or should I be concerned about something else going on?