Fish live in the water and breathe by absorbing oxygen through their gills. Fish are cold-blooded animals, so their internal body temperature is influenced by the environment. Many fish have scales and use their fins to swim. Fish have a spine but do not have external ears or eyelids. Fish also have air bladders, which keep them afloat.Know More
A fish's gills are special organs which contain thousands of small blood vessels called capillaries. The gills constantly filter oxygen out of water and into the fish's bloodstream. Gills are also useful for excreting waste from the fish's bloodstream. Some fish, such as sharks, have multiple gill openings.
Fish have sharp or smooth scales that protect the fish from injury. Fish create a mucous covering over the scales, which helps protect against infection by trapping bacteria and keeping it from entering the fish's body. This mucous also reduces friction, which helps the fish easily swim through the water.
According to the International Union for Conservation for Nature, about 800 species of fish live in the United States and there are 30,000 species worldwide. Scientists believe that thousands of fish species have not been identified. Fish are a more diverse species than any other group of vertebraes.Learn more about Fish
Betta fish can breathe oxygen both from the water through their gills and directly from the air above the surface of their bowls for small periods of time. The fish can live for a short period of time in oxygen-deficient water though they thrive in small aquariums. Betta fish were first spotted in Southeast Asia, where they live in rice paddies, drainage ditches and flood plains.Full Answer >
Saltwater fish osmoregulate by transporting salt out of their blood and into the surrounding water through specialized cells in their gills. Saltwater fish also only produce a very small amount of urine in order to retain the maximum amount of water.Full Answer >
Three common characteristics of all bony fish are that they have a bone skeleton, externally fertilize their eggs and have bony platelike scales. Bony fish are also known as Osteichthyes, and cover a diverse group of fish of over 20,000 species.Full Answer >
How long a fish can live out of water depends on the species of fish, as some fish can survive for up to a few days while others can only survive for minutes. The fish that can survive for a few days without water do so by breathing the air or by absorbing it through skin.Full Answer >