I would worry about that much confined weight on anything that hasn'r been reinforced extremely well. If you can position over a load bearing wall, or reinforce the entire are well you should be o.k. but the risk is huge if there is any doubt.
As far as the original question, Oscars and Jd's (1 or two of each ) would be great. But as has been said repeatedly. If I had 180 gallons of fish tank it would have a pair of jags no question in my mind. I am an oscar nut, but still think a full grown jag is the most awesome cichlid around. I had a friend who owned a 15 incher, and it was a bad dude !!!!!!!!