The last time I went to the National Aquarium In Baltimore was 24 yrs ago. It was great then.
This time it was a little disappointing. They used to have more tropical's and the layout was better. Crowds were crazy, even on a weekday. We went midweek. Yes they added the dolphin show, which was nice, and the 4-D short movie, which was the highlight as far as I was concerned, but I felt it took to much time and kept me away from the actual Aquarium itself. When you purchase tickets in advance they don't tell you its timed tickets for these, so that when you get there you have to do those first. If i would have known this I would have skipped it and went straight to the Aquarium part itself.
Final thoughts: If you live closer to the Camden Aquarium in New Jersey, go there!
Side note: Go to the 27 floor of the Baltimore World Trade Center Building for $5..worth it, great view!