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 »

www.reference.com Pets & Animals Marine Life Fish

Fish gills act as the equivalent of a mammal's lungs by taking in oxygen and releasing carbon dioxide. Oxygen and carbon dioxide travel across small, thin-walled blood vessels in both lungs and gills. In terms of evoluti... More »

www.reference.com Pets & Animals Marine Life Fish

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 »

Fish gills act as the equivalent of a mammal's lungs by taking in oxygen and releasing carbon dioxide. Oxygen and carbon dioxide travel across small, thin-walled blood vessels in both lungs and gills. In terms of evoluti... More »

www.reference.com Pets & Animals Marine Life 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... 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 »

Blood that reaches the lungs travels throughout a network of small blood vessels, where oxygen moves into the blood and carbon dioxide moves out of the blood, according to the National Heart, Lung and Blood Institute. Th... More »