Two fish

When, at last, the pool was finished to my satisfaction, I bought two beautiful koi. One black and one white. They would circle around the pond and each other in an intricate and balanced dance. I christened them Yin and Yang. But the effect was never achieved. The fish would confine themselves to one side of the pond. Or sit, motionless, apart from each other. It was only when I added a third fish - a small brown, unremarkable thing - to the pond, that Yin and Yang began to dance.