At least in the US, a significant amount of the fish you eat in high end restaurants, sushi restaurants and fish markets is never frozen.
It is packed in ice and kept very cold, but not frozen.
Supermarkets are more likely to stock frozen/previously frozen. Lots of commodity seafood is frozen when caught.
Source: Spent a season offshore fishing for swordfish/tuna. Worked in the warehouses that unloaded and shipped the same. Drove the truck that delivered the fish.
It is packed in ice and kept very cold, but not frozen.
Supermarkets are more likely to stock frozen/previously frozen. Lots of commodity seafood is frozen when caught.
Source: Spent a season offshore fishing for swordfish/tuna. Worked in the warehouses that unloaded and shipped the same. Drove the truck that delivered the fish.