White anchovies are not actually a different type of fish to the common anchovy but are simply prepared in a different way. Where the latter are traditionally cured in salt and brine and then packed in olive oil, white anchovies are salted and pickled in vinegar and herbs. The result is a plumper fillet with a firm texture and subtle tart flavour, markedly different from the pungent taste and coarse texture of the more traditional anchovy. They can be quite expensive, but worth it.