He puts his aquarium upside down in his pond: the result is quite appealing!

Before filming this video, this man had previously made a video in which he demonstrated how to "expand" or enlarge a pond, simply by taking an aquarium, standing it on its end while leaving space for water, air, and the fish to enter the aquarium from the bottom of the pond so that the aquarium could be filled up with both water and fish!  

An ingenious idea! Apparently, his carp agree, as they seem to be really excited to have this "tower" from which to observe the surrounding environment and are crowding up inside!