What is the ruling on eating frozen fillet fish imported from Vietnam, whose body is not covered by scales (fals or saft)?

There is no harm in eating fish and marine creatures, due to the generality of Allah's Almighty saying: "Lawful to you is the pursuit of game from the sea and its food," and the Prophet's (peace be upon him) saying regarding the sea: "Its water is purifying, and its dead are lawful." This excludes anything proven to be medically harmful.