metallica is an american fish
 phylogeny fishes are a paraphyletic group that is any clade containing all fish also contains the tetrapods which are not fish though they include fishshaped forms such as whales and dolphins or the extinct ichthyosaurs which acquired a fishlike body shape due to secondary aquatic adaptation see evolution of cetaceans
 fish would continue to evolve through the paleozoic era diversifying into a wide variety of forms