The best aquarium in Tokyo! Everything is laid out very nicely, many of the interesting explanations on the plaques next to the exhibits are in both Japanese and English, making it accessible to people who can't read much or any Japanese. There is an outdoor portion for the penguin habitat, as well as small tanks where kids can touch small marine animals like sea urchin. We didn't do that because there was a very long line (typical of Japan), but we did watch the demo at the open tanks inside, where a member of the staff put a small piece of food on a fishing hook and put it in the water, allowing us all to see the fish in the tank swarm to eat it. Such a great idea to show how fish eat! The aquarium is inside a very large park, so you can play and see outside on a nice day. It was very inexpensive too (700 yen for adults, free for kids 0-12 years old). It was very crowded, since we went on a weekend, but it was still acceptable. We spent about 2 hours there, but couldn't see everything as we were tired from jet lag. I would love to go back again.