In 1994 I hired a mini digger and dug a Garden Pond. It was first lined with carpets which were retrieved from various people in the the village. It was then lines with butyl rubber.
The pond remained water tight for many years, but eventually sprung a leak, filling up in the winter rains, and nearly completely drying up in the summer.
We did stock it with fish. The Heron was attracted, and then we lost many in the frost. The pond froze over, not a problem for the fish. It then rained hard one day leaving inches of water on top of the ice. The fish managed to get into this layer of water. It then froze again.