What do you think of outdoor aquariums in the garden?
There are many garden ponds and waterfall designs which include live fish and plexiglass viewing panes.
The main problem with outdoor aquariums is the maintenance to keep it looking good.
At one house, we built a waterfall & holding pond (small) on the slope in the front yard.
At first it looked awesome but as time passed, it became harder and harder to maintain its beauty.
Eventually we scrapped the water idea and went with rocks.
The X had an indoor waterfall collection. She was a water sign and loved the sound of running water (it soothed her).
A few pictures for ideas of garden aquariums at pinterest...
Some ideas for backyard waterfalls at pinterest...
Ideas for waterfalls w/ fish ponds at pinterest...
Once you look at plenty of designs you can create working designs based on the features you really like and create something new and different.
There's also plenty of sites on the web which can tell you what does and doesn't work.
Moving water is less likely to get algea and mold but some moss can be appealing.
Also, you must pick your fish and aquatic creatures wisely for the area and the habitat.
Living creatures need a sustainable environment or they get sick & die. Ya gotta do some research.