Really folks I thought I had seen it all until I watched this video where the owners of this Koi pond put an inverted fish tank on the surface of the pond. I’m guessing that they then removed the air from the fish tank causing it to fill with water from the bottom up. This then made it possible for the Koi to swim up into the fish tank for viewing by for visitors.
I’ve got to admit that this is a very clever idea and I may have to try it this year in my Koi pond. I can almost guarantee I’ll have the only Koi pond around with this arrangement.