Fish have gills because these organs are used to extract oxygen from the surrounding water in which a fish lives. Gills are different from lungs because gills generally work unidirectionally: water moves in one direction... More »

All frogs begin their lives as tadpoles that breathe underwater using their skin and gills. As the frog grows, lungs begin to develop and the frog loses its gills at it begins to metamorphose. More »

Gills work in fish in much the same way as lungs do in mammals, as they help take oxygen into the blood and release carbon dioxide. Fish draw water into their mouths, which then travels past the many tiny blood vessels i... More » Pets & Animals Marine Life Fish

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 »

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 »

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 »

Squid extract oxygen from the water using gills, just as fish do. These gills are located in the squid's mantle, the soft but muscular cavity behind the squid's head. More »