I've been to the Monterrey Aquarium, and i Loved the Kelp tank there.
The Georgia Aquarium, it was ok, the Whale sharks were really cool, but the rest was just ok. It was very crowded and didn't take long to see everything twice....
The Aquarium on Guam was very disappointing. Being an aquarium, you would expect them to have most of their fish easy to see, and in a great setting, after all you are paying $21 just to see the fish. Well I found snorkeling for free in the chest deep reefs offered a much higher concentration of aquatic life and a larger diversity as well.
The Mystic Aquarium, it was just OK for me as well.
The Tennessee Aquarium was awesome. Cost to enter is about $25, but it's worth it. They have so much to see, and wide range of habitats. My favorites were the freshwater native river tanks. the catfish and gar were HUGE. In their smaller native tanks I love that they used live plants as often as they could.....
The Indianapolis Zoo, Great place to visit, and they really did a great job of making each enclosure look like their native habitats. They have a pretty nice Waters building with a touch tank. easy to spend a lot of time in there.
The Birmingham Zoo was just ok. The predator building was pretty depressing though as the enclosures were small and most of the animals looked "depressed". they did have an elevated outdoor pond with glass viewing on the sides. It was a cool concept, however the acrylic was scratched and there was so much algae it was difficult to see anything in the pond.
The Cincinnati Zoo was a lot of fun years ago when I went, the Polar bear area was the best part though...
The Knoxville Zoo was pretty cool, down side is many exhibits were closed. Positive is they were closed so they could revamp the areas to make them more natural for the animals. The zoo staff was very friendly.......
The Nashville zoo was pretty nice, try to avoid going on a weekend though...
I know there are more I've been too, just to much to write for now.....