Unpackaged cooked yellow croaker cannot be eaten after three years of dry storage. According to the principle of food safety and common sense, it is not recommended that you eat cooked dried yellow croaker that has been left unopened for three years. Although this dried fish product has a long shelf life, long-term storage may lead to quality degradation and food safety problems. Here are some considerations:

1. Shelf life and storage conditions: Even food sealed in vacuum packaging may be affected by unfavorable factors such as oxygen, humidity and temperature after long-term storage. Long-term storage may lead to oxidation and mold growth, thus deteriorating food.

2. Food safety: Food stored for a long time may be affected by microorganisms, toxins and chemical changes. These factors may lead to an increased risk of food poisoning or ineptitude to eat food.

3. Storage environment: If the cooked dried croaker is exposed to humidity, direct sunlight, high temperature or other unsuitable storage environment, the quality and safety of food may be more easily affected. In order to ensure food safety and avoid food poisoning, it is suggested that you discard the unopened dried yellow croaker that has been stored for three years. If you have any questions or uncertainties, please consult professional organizations or local food safety agencies for more accurate advice.