The sardine is a small, oily, intensely savoury schooling fish — the European pilchard (Sardina pilchardus) and its relatives in the herring family — with a bright silver belly, a blue-green back and a soft, fine-boned flesh dense in omega-3 oils. Frankly "fishy" in the best sense, rich and almost meaty for so small a fish, it is grilled whole over coals along the Mediterranean and, most famously of all, packed in oil into the tin that made it a worldwide pantry staple.