Herring

Herring can be called the most ancient type of fish. We first see the mention of it, back in 705. At the beginning of the 20th century, when the herring industry was massive, its fallen scales were collected and processed into artificial mother-of-pearl and pearls. 

Surprisingly, herring is useful for preventing flu and colds. And this all is because the herring contains the essential amino acid lysine, which has an antiviral effect.