Can We Preserve Raw Fish In Oil?

Could you do the same thing with fish, like sardines? They're packed in oil aren't they, in a can?

You can do that but not in metal containers. It is best to marinate everything in glass. I recommend that you cure the fish for 1-24 hours in lemon juice, pour off the lemon juice and then add your vinegar but again, it is likely to last no more than 2 weeks without getting unappealingly rank but still very nutritious. I discussed preserving meats for long periods several issues ago for my survival kit.