Fish are aquatic vertebrates that have a vertebral column called a spine. Fish are normally shaped like a tornado. Most, fish are ectothermic, or cold-blooded. Two of the exceptions are the tuna and the Pacific salmon shark, which can raise their body temperature to a certain degree.. Fish have a lateral line, a two chambered heart, gills used for respiration, no external ears, and no external eyelids. There are 30,000 species of fish.
Some examples of fish are: catfish, sharks, salmon, trout, and sturgeon. Some Chordates are fish, such as the X-ray tetra.
Some examples of fish are: catfish, sharks, salmon, trout, and sturgeon. Some Chordates are fish, such as the X-ray tetra.