It is my limited understanding that the fishes aren't ready for breeding till they are bigger/older. There are other explanations for why your fish are doing this. Could be lack of oxygen, could be them hunting down food stuff that lives in the falls, could be they are just playing in their new digs and enjoying themselves.
I don't suppose you see any foam on the water do you? I think that would be a sure sign of spawning.

We did the same thing a couple of years ago. We lost all but four over the winter. The following spring the four spawned. We had hundreds of babies. We had about 70 that lived and for the past several years this number has been pretty much constant as they live and breed.

From experience gold fish are born dark and turn yellow starting about 4 months. They can start breed at some point after that depending on the weather, water temperature, etc.

Since you do not know the age of your fish when you purchased them it is possible that they could spawn the first season.

The oldler fish may turn white.

My fish love to swim "against the tide" - facing against water flowing from the hose and/or waterfall. There are only 2 of them in a 160 gal pond with plenty of oxygen. I think they like it.

Anne

bluesunflower - there isn't a lack of oxygen right now thankfully, and yes there is some foam on the top, but that is more likely either from the barley straw that is working to prevent algae, or the new UV lights that my husband put in last week to also kill off algae. I was looking closely at the foam and don't think it's fish eggs.

knuttle - all these fish have their full colors now, so they aren't that young. I'm just not sure how old they are.

Guess we'll wait and see what happens!

I bought some feeder fish and put them in my pond display and they have spawned in there. There are dozens of little goldfish minnows in there now. I know it had to be those fish because there weren't any others in there that were older. These feeder fish were only a couple inches long. And still about 3" long, but lots of babies in there now.