All fish, sea turtles, sea snakes, although the turtles "fins"
are actually webbed legs, and the sea snakes do not have true fins,
just a flattened tail to provide locomotion.
Yes, Salmon do have fins and scales like most fish (although som
fish, like catfish, do not have scales). I have never heard of a
fish without fins, although eels have less fins than many other
fish.
The scales tend to be small and most fish vendors will sell
salmon fillets with the skin and scales still on (although some
people think the scales are unpleasant).