Fish use their gills to breathe by extracting oxygen from the surrounding water. The oxygen that fish and other animals with gills use is bonded to hydrogen molecules and is dissolved in the water. Water molecules are co... More »

Fish require oxygen for survival just like other animals, but they filter it from water using specialized organs called gills. A fish draws in oxygen-rich water and passes it through its gills. The organs absorb the oxyg... More »

Fish have adapted to their environment through the evolution of gills, swim bladders and fins. Gills allow fish to absorb oxygen from the water, swim bladders allow fish to maintain an appropriate level of buoyancy and f... More »

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 ... More »

A fish breathes through its gills, extracting oxygen from the water. Other sea animals, such as whales, breathe oxygen from the air because they are mammals. More »

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... More »

The vast majority of crabs have gills, much like fish, which extract oxygen dissolved in water. Even when they are on land, the gills can still absorb oxygen as long as they are kept moist. There is also a small selectio... More »