What are different species of fish species?

fish species are a very diverse set of aquatic animals adapted to live under water. The main characteristics of shared mostly fish are that they live in water, breathe with gills, have scales and swim with their fins. The species is the most specific biological category and refers to a group of similar animals that can behave with each other, but not with other species. Fish species have adapted to many types of water locations and can therefore differ very much. One basic resolution can be distinguished between sweet and salty water fish.

Fish are classified as vertebrates, which means they have a spine or spine. Vertebrates include ground animals such as birds, mammals, reptiles and amphibians. Fish are actually so diverse that there are more individual fish species than all other vertebrates. It is estimated that the total number of fish species is about 20,000 or more.

There are three wide types of Groups fish that developed along similar lines. One of the groups are koStandy fish that include many species that usually evoke the word "fish". This group includes, for example, gold fish and many freshwater sports fish such as bass or perch. Another group is called cartilage cartilage because they have cartilage skeletons instead of real bones and this group includes sharks and beams. A small group is classified as a jaw and this group includes the most primitive of all fish species, one example is Lamprey.

bony fish are by far the largest group of fish species. The estimates of their number ranges from approximately 20,000-25,000 species. The cartilage fish consists of about 600 species. The jaw -free group has about 45 species.

fish species have the greatest differences in the size between any group of vertebrates. The largest whale shark can weigh 20 tons (18 metric tons) and grow about 50 feet (15 m) while the smallest is smaller than the inch longý (1.5 cm). Fish come in a large number of colors and some are very bright, such as those that have adapted to color coral reefs. Other fish can be matte color of rocky current.

The difference between fresh water and salt water has very important consequences for biological chemistry of fish. Therefore, almost all fish species live exclusively in one or the other. The exception is salmon that spends lives in the ocean and returns to fresh water to emerge. Some freshwater eel will reverse the process.

The first fish species appeared almost 500 million years ago, so the fossil record contains a wide range of prehistoric fish. One type of fish, coelacant, was known from different fossils and thought he had been extinct millions of years ago. Scientists were therefore very surprised when one was caught in waters outside South Africa in 1938.