Sardines or herring will be safe indefinitely if you store or freeze it according to USDA recommendations. But it would be best if you kept in mind that after fish have been frozen or are left in the refrigerator, flavor and texture will lessen after lengthy storage.

How long does herring last in the freezer?

Properly stored, it will maintain best quality for about 3 months, but will remain safe beyond that time. The freezer time shown is for best quality only – canned smoked herring that has been kept constantly frozen at 0°F will keep safe indefinitely.

Why should you not freeze fish?

But let's be honest, the best way to eat fish is to not freeze it at all and go straight from the water to the plate. Fish flesh breaks down as the delicate cell membranes burst when they freeze and thaw. Much of the time though, eating fresh is just not an option—especially if you have a big haul.