I tried a large mouth bass in a 75 gallon tank. The bass was 4-6 inches in length. I just wanted to observe it's behavior and let it go after a couple of weeks. However, after 4 days of not eating and just hanging around a rock formation I decided it was best to let it go. Mostly the not eating thing had me worried.
We all seen the tanks at various places but it would take a lot of work and preperation.