The supporting tissues of Vertebrates, known collectively as the skeleton, cover a wide gamut of anatomical structures, from the softest connective tissue to the hardest material in the body, tooth enamel. Depending on the ontogenetic level of an individual fish, the skeleton is made up of connective tissue, notochord, cartilage, bone, or some combination of the above. The fish skeleton, the oldest of the Chordate phylum, is a complex mixture of elements that emerged in evolution as a result of the interaction of the fish with their environment. The structure of the fish skeleton has been the blueprint for the skeletons of other vertebrates, including that of man. Fish osteological nomenclature has not attained yet the level reached by the terminology used in other sciences, such as physics and chemistry. Even Linnean binomial nomenclature is better organized since it follows clearly established rules.