Canned salmon can be stored for up to three years when left unopened, but you can still safely use the leftovers from an open can if you store the salmon correctly in the refrigerator. Drain off the liquids before you refrigerate the salmon so it's ready to eat at a moment's notice.
After you open it, canned salmon shouldn't be left in the can. Don't wait to refrigerate the leftovers. Storing them immediately keeps the salmon safe to eat. Transfer the salmon to a storage container with a tight-fitting lid. You can store the fish in a 40 degree Fahrenheit or cooler refrigerator for three or four days. If you need to store it longer, keep it in an airtight container in the freezer for up to three months.