Here are two of my four mini koiponds in bottle caps. They are little pendants with hand made and painted kois, swimming in a pond with resin. The water lilys are nail canes. I have two others that look more natural, I will show them later too.

They are both available at my shop (german only, if you live elsewhere, please contact me!)
http://schiraki.deviantart.com/art/Bottle-cap-koiponds-576824288