Anchovies are small, common saltwater fish, with over 140 different species typically classified as oily fish. These slender, greenish fish often have a hint of blue. The traditional method of processing and preserving anchovies involves gutting and salting them in brine, allowing them to mature, and then packing them in oil or salt. This process gives anchovies their characteristic strong flavour and transforms their flesh to a deep grey colour. Anchovies pickled in vinegar, as in the Spanish dish boquerones en vinagre, have a milder taste and retain a white flesh, offering a different culinary experience.