All fish share two features: they live in h2o and they may have a backbone—They can be vertebrates.
Other than these similarities, nevertheless, many of the species In this particular team vary markedly from one another. Fin fish like salmon have gills, are protected in scales, and reproduce by laying eggs. Eels, Against this, have worm-like bodies and exceedingly slimy pores and skin. Lungfish gulp air. Whale sharks, the biggest fish, give beginning to Reside youthful and eat only small fish, squid, and plankton. Some species, like the weedy sea dragon, are so weird they appear almost unreal.
Fish have designed Specific senses, too. Since drinking water transmits Seems, disperses chemical compounds, and conducts electrical power much better than air, fish count much less on their eyesight and even more on their own hearing, style, and smell. Several can detect movement while in the h2o using a Specific row of scales with sensors referred to as the lateral line. Other people can discover their prey and even navigate by detecting electrical fees.
A person cause fish are so varied is usually that 70 p.c from the World is roofed in water. The animals In this particular team live in a variety of habitats starting from coral reefs and kelp forests to rivers, streams, along with the open ocean. Yet another is the fact fish are incredibly previous over the evolutionary scale. In keeping with fossil documents, they are already in the world for much more than 500 million a long time! The full variety of residing fish species—about 32,000— is larger than the full of all other vertebrate species (amphibians, reptiles, birds, and mammals) merged.