Adult tautogs, also known as blackfish, are usually dark colored – black, brown or dark grey – with blotches of darker color on the sides. Small juveniles are often green in color. Whether called tautog or blackfish, this saltwater fish is popular with anglers. Adults average about three pounds in weight. Their mouths have large teeth able to crush mussels, clams, barnacles, lobsters, crabs, and other hard-shelled prey. We sometimes find tautog in New York Harbor, and they have been known to stray up the Hudson, especially in years of drought when salt water moves far up the river.