Miss C wrote a really neat article at mental_floss about really cool aquariums. This one to the left is a Birdcage Fishbowl, an early 19th century contraption to keep both fish and fowl:
This antique Birdcage Fishbowl is an odd pairing, with a birdcage on the bottom and a fishbowl on top. There is a bubble inside the fishbowl, which the bird can rise up into. This achieved the illusion that the bird is in the bowl with the fish!
Link - via Miss Cellania
And of course there is always the ever-popular Macquarium: http://vividpicture.com/aleks/macquarium/
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