A fish is any aquatic vertebrate animal that is typically ectothermic, covered with scales, and equipped with two sets of paired fins and several unpaired fins. Fish are abundant in the sea and in fresh water, with species being known from mountain streams as well as in the deepest depths of the ocean.
Food prepared from fish is also called fish, and it is an important food source for humans. They are harvested either from wild fisheries or farmed in much the same way as cattle or chickens. Fish have had a role in many cultures through the ages, ranging from deities and religious symbols to the subjects of books and popular movies.
A typical fish is ectothermic, has a streamlined body that allows it to swim rapidly, extracts oxygen from the water using gills or an accessory breathing organ to enable it to breathe atmospheric oxygen, has two sets of paired fins, usually one or two dorsal fins, an anal fin, and a tail fin, has jaws, has skin that is usually covered with scales, and lays eggs that are fertilized internally or externally. They are a paraphyletic group that is, any clade containing all fish also contains the tetrapods, which are not fish. For this reason, groups such as the Class Pisces seen in older reference works are no longer used in formal classifications. People can know about more wild animals from the internet.
Home >>fish
Fish are ancient water dwelling creatures found all over the globe. They are the worlds oldest vertebrates, with the first fish appearing some 500 million years ago. Today more than 24,000 species populate the waters of the world. Fish are vertebrates and breathe with gills, which draw oxygen from the water and into the bloodstream. Most have skeletons, though sharks and rays have skeletons made of cartilage. Nearly all reproduce by laying eggs and are also exploited by recreational fishkeepers.
Fish are ancient water dwelling creatures found all over the globe. They are the worlds oldest vertebrates, with the first fish appearing some 500 million years ago. Today more than 24,000 species populate the waters of the world. Fish are vertebrates and breathe with gills, which draw oxygen from the water and into the bloodstream. Most have skeletons, though sharks and rays have skeletons made of cartilage. Nearly all reproduce by laying eggs and are also exploited by recreational fishkeepers.
