[ALS Mako]

joey, i would not use frozen fish for sushi or sashimi. when you freeze fish at home (even vacuum sealed) the water in the cells of the meat expands, breaking the cell walls. notice if you thaw the fish out, there is always extra water from the fish. the fish is still edible but i would not suggest eating raw.

marty- just to inform you, it may be law- but seldom is fish from sushi restaurants from frozen fish. most of the fish is just plain old iced down fish that the restaurant buys from a purveyer. only fish that come from far away are frozen for shipping, and that fish is blast frozen to preserve the texture of the meat. if properly handled and cleaned, there should be no problems.

when i make sushi or sashimi, 1) rinse off the fish and wipe away as much slime as i can with paper towels, 2) gut the fish, make sure you get all the blood out (especially the kidneys) and rinse well and pat the fish dry. 3) filet the fish. 4) rinse the filets in heavy salted ice water (depending on how "dirty" the filet is and what kind of fish, i might skip this step and just wipe the filet with clean paper towels)- then dry fish with more paper towels.
5) on a clean cutting board/ cut fish into portions and serve. 6) if you are doing this ahead of time or are worried about getting sick, this is when i would freezed the fish (already portioned out and on a plate- throw the whole thing in the freezer covered with plastic wrap)