The Kinds of Unique Fish at a Glance

Fish are vertebrates, just as we are. That is, they are animals with backbones. All vertebrates, mammals, birds, reptiles, amphibian and fish have a backbone. There are other animals that are called fish, such as shellfish and starfish but they are not true fish. They are invertebrates, or animals without backbones. Whales and porpoises are not fish either. They are mammals that have adapted to life in the sea. Whales and porpoises must swim to the surface to breathe air. Read more.