FISH IN OUR WORLD
Fish are a class of aquatic vertebrates. The combination of gills, fins and the fact that they live in water makes them different from the other animals. Fish are cold blooded animals hence they live in water with the expectation of tuna and mackerel shark families. Scientists group fish in three main groups, they are divided in these groups because of the structure of their mouth and the type of skeleton they have.These are jawless fish, cartilaginous fish and bony fishes. The main characteristics of fish are, they use gills in breathing, their bodies are covered with scales, they use fins for movement, they all live in water and lastly they are cold get blooded animals or they are ectothermic.