I have a small pond that I dug myself four summers ago. It ranges from 2 to 4 feet deep and is bare liner. We leave our koi in the pond year round but build a structure over it for the winter and the fish have done well with this arrangement so far. I sort of got into the hobby by being naive. I bought several small koi not realizing that an indoor aquarium would not be a winter solution for long so faces with the choice of re-homing my fish or building a bigger pond........I started digging. My neighbors joked that I was digging a grave and must be quite upset with my husband. Now they enjoy the water sounds of my pond from their deck. Nice to have found this forum as there are not many ponders in my neck of the woods..