So what is that picture all about? Basically, it is an aquarium where you can feed the fish. Nothing too unusual?
Rather than feeding from above, this fish tank has holes in its sides where you can drop the food in, and wait for the fish to poke their heads out and eat!
As far as I can tell from the explanations, the effect is achieved because the tank itself is normally otherwise sealed, so the pressures involved keep the water from emptying out onto the floor. I do wonder if they have to monitor the place during the night, in case fish end up leaping out onto the pavement.
Check over here for the original source of these pictures.