I have seen pictures of bird cages that were surrounded by an aquarium. The result was that it looked like the bird were in the water too with the fishes.
I'm sure it would be very easy to put plants instead of birds in the middle section.
Sadly though, I cannot remember what they were properly called. But it should be noted that your idea will not lead to a dead end, there is information about it out there, and also, these pictures that I saw were from the Victorian era, so this sort of idea fits right in with that time frame.
