Fish have got scales, they are oviparous and they can be carnivores, herbivores or omnivores. Fish always have played an important role in their relationship with man, since they are a source of important power, by that the industry of fishing has specialized in its capture and the reproduction of these animals to facilitate their consumption by humans.
The skin of fish is slippery. Thin, bony scales protect their bodies. Fish breathe using organs called gills. Gills are thin red membranes located at the back of the fish's mouth which open to the water through slits in the side of the head. Exchange of gases occurs here as the water passes over the gills which absorb oxygen and expel carbon dioxide. Marta Barrera Collazo y Nerea Pintescu Borta, 4° de Primaria.