Are all the koi in the pond acting this way or only some of them?
Have you added anything new to the water or recently did a large or 100% water change?
I only have 2 and they are in a 60 gallon fish tank right now. And both of them are acting that way. I have 3 gold fish with them and they are okay. The koi act like they are anixous about something.
There are 2 possibilities here and they are that the Koi, if adults, could be beginning to mate as this is the time of year for that or they are in fear of something.
If the fish are indeed starting to mate then there is nothing that can be done short of seperating the fish.
If fear is causing the problem then what needs to be done is supply some sort of hiding places in the tank, i.e, thick foliage, artifical plants, etc.etc. It would also be advisable to keep the hood light off so as to minimize any stress the fish may feel.
As a precaution, if you haven't already done so, it would be good procedure to test the water for levels of ammonia, nitrites and nitrates. If you're unfamiliar with water testing a water sample can be taken to your local pet store where they can assit you and will most likely test for free. Proper test results would indicate ammonia and nitrites=-0- and nitrates=20ppm or lower. Deviant results would indicate a serious water quality problem.
I tend to not believe that there is a water problem as the goldfish are behaving fine but it's always better to verify.