Next to the main U.S. Department of Interior building is a koi pond. Well not exactly a koi pond, more like a wildlife pond with turtles, dragonflies, ducks, and of course koi. It sits with in view of Constitution Avenue in Washington D.C. ( http://www.doi.gov/ )
I saw the turtles sunning themselves among the boxes of marsh reeds. Walking closer, I saw a school of small red koi with two large black ones. They looked like a drill team swimming in unison around the boxes and turtles. Sometimes, they would encounter a large koi, and change direction. No stragglers or confusion. Just turn about face and swim!
I understand why people enjoy koi ponds. It is peaceful to watch them swim with their tail fins floating in the water. Their colors lend brightness to the murky water.
Koi are members of the carp family. More info and pictures can be found at : http://www.vcnet.com/koi_net/