The sprat is a tiny, silver, oily schooling fish of the North Atlantic, North Sea and Baltic (Sprattus sprattus), a close cousin of the herring and sardine rarely longer than a finger. Cheap, abundant and richly flavoured, it is fried or grilled whole and eaten head, bones and all, but is best known cured — hot-smoked into the golden Scandinavian "brisling" and packed in oil, or salt-ripened into the spiced Baltic kilu and sprots that fill the little flat tin.