I am at a resort in AZ on spring break. Where we are staying they have a koi pond. Looks seriously overstocked and on the verge of trouble. One of the things I saw that I have never seen before- almost all of the fish are lined against one side of the pond and all are nose/mouth up against the wall. Sitting pretty still.
I saw one jump/breach in just a few minutes (one that was not sitting still by the wall) and one sitting fins clamped. Also a tumor on one.
I might chit chat with the owner tomorrow and see if I can share some health concerns without offending them.