If the fishmonger advertises sushi-grade fish, ensure that it’s not stored with non-sushi grade fish. The fishmonger should also change gloves before handling the sushi-grade fish.
To safely thaw the fish, remove it from the freezer and place it in the refrigerator. Ensure that there’s plenty of space around the fish so the cool air can circulate. Only freeze the fish if it hasn’t been frozen before. Ask the fishmonger about this before you buy the fish since many seafood counters freeze their fish before selling them.
You can use this piece for making sashimi or nigiri since it doesn’t contain tendons which could make the bites chewy.
You should also remove the other half of the fish piece from the skin by holding your knife parallel to the skin. Slide the knife between the skin/tendon and the meat of the fish.
If your piece of fish is large, you may want to cut the sashimi into 9 pieces. The pieces will be thin chunks of fish that you can serve immediately. [8] X Research source
Each slice of nigiri should be about 1 to 1. 5 ounces in weight. They should be thin and uniform.
