Menhaden. An oily fish of American Atlantic waters, it has a large head with no scales and a blotch just behind the operculum with more irregular dots behind. Its back is dark, with blue or green or brown shades, and the sides are silver with a bronze sheen. Menhaden are used mainly for fertiliser or as bait being almost too oily for human consumption, though they have been tinned under various misleading names. Pogy may be derived from an American Indian word for fertiliser.