Wow, would be interesting to see. In my travels across Asia I've seen some truly huge aquaria, often hidden in the most unexpected places Seems like the bigger the better, with big and extremely frequent water changes, are the thing for success. As great as they can look, and as wonderful a pet as I'm sure they can be, I'm firmly in the camp of large amounts of smaller fish in tanks of those sizes. Imagine hundreds of cardinals etc - for me the effect is greater and, my own, worries about how humane it is are allayed. But as you say, plenty of healthy fish have been kept in tanks of those size.