They're wet. They're slippery. And frequently, they're delicious. Yes, fish, squid and other treasures of the sea are vital to life in Japan, but there's more to their story than what comes on your plate. A good place to learn more and see flippers in action is the Shinagawa Aquarium, where sharks, jellyfish, penguins and other ocean dwellers are all on prominent display.
Dozens of gargantuan tanks re-create many of the world's water environments: from the Amazon River to Tokyo Bay. The largest and most impressive of these tanks weighs in at 500 tons, with a 22-meter glass tunnel along the bottom. Here manta rays and sea turtles swoop bewilderingly close overhead.
Just past the tunnel is a hands-on area where kids can touch live starfish and hermit crabs. Little ones may also enjoy the dolphin and sea lion shows, but be warned: these fill up quickly and you are asked not to save seats with your belongings. I recommend arriving at least 15 minutes before show time.
The man-made pond outside has several foamy, nasty spots, but ducks and giant carp await your breadcrumbs in the cleaner area near the boardwalk. As for your lunch, the corndog/yakisoba variety is available outside, with a family restaurant-style eatery positioned near a whale-fin sculpture.
If you've still got energy to burn, head over to Shinagawa Kumin Park (Keep your Aquarium ticket, though. Re-entry is permitted). Just follow the bicycle path away from the Aquarium with the pond on your right. You'll pass lots of playground equipment (and mosquitoes, so be prepared), a fountain/courtyard space and a public pool. There's also a baseball diamond where you can sometimes catch local teams playing pickup games.