Also I don’t think sushi restaurants typically have any special freezers for this. You can reach the required level in a regular commercial freezer. -4F for one

Also I don’t think sushi restaurants typically have any special freezers for this. You can reach the required level in a regular commercial freezer. -4F for one week. Any commercial freezer gets that cold, and that step is taken by the wholesalers anyway for any sushi that requires it.