From the outside this place looks like a gift shop or something like that, but this is the place to go for sashimi-grade fish in Madison if you want to make sushi at home (if you're in Madison, you can make better sushi at home than you can get at a restaurant, for a lot cheaper!)
They get in fresh fish every other Saturday but aside from that they have plenty of frozen on-hand. I'd give them 5 stars but this place is really small, really crowded, and the couple of times I've been there, really busy. The people working there are very nice and friendly which is good because you will need their help to find what you want without randomly digging through the freezers!
Probably the only place in town where you might find Anpanman pastries by the checkout or Pocari Sweat powder...
Cash only.