Preserving/curing/pickling already frozen fish

I have alot( like 5++kilos) of frozen fish. I have no more storage space in my freezer. How can i preserve these frozen fish in a way that would not require refrigerating them?

I was thinking of smoking but then smoked fish needs to be refrigerated. Anyone has any preservation method or recipes for frozen fish?

oh, and fish is hoki fish. I think its also called hake. The type of fish in your filet o fish.