Once it's cold, yes. But it won't taste very nice when you come to eat it. And you can't recook it, so you'd have to have it, say, flaked up on a salad.
For instance, I make a sauce from a roux, add chucks of Salmon, prawns etc. Top with potato and sweet potato mash and freeze for when I need it. But that means that the salmon wasn't actually cooked before freezing.
for tea last night i cooked some salomon fillets in the micro, made up a hollandaise sauce and stirred both into some cooked pasta with some peas. as usual, i made far too much so the left-overs have gone into the freezer. i do this regularly and the salmon is fine.