What do fish breathe in water?

Answer 1

fish breathe in the water the same way humans breathe in the air fish breathe through there gills which help them breathe if humans went under the water we wont be able to breathe and if went in the air they could only do it for a tiny bit .

Answer 2

Fish breathe oxygen, the same as land animals, so it is important to make sure their water is oxygenated, with an aquarium pump. They extract it with their gill rakers (if you lift the gill cover on a dead fish you will see these- they are red because the blood flows through them and carries the oxygen "combed" from the water round the fishes' circulatory system. A fish has to keep fresh water flowing through its gills, hence the constant mouth-and-gill action a healthy specimen will display. Some species have such a high oxygen demand that they have to swim constantly forward to replenish the water in their gills.

As for the swimming, it's a simple muscular action, and a fish is perfectly shaped for movement in water. Some species can reach impressive speeds, such as barracuda, sailfish and bonefish.

Answer 3

Fish have gills instead of lungs. They suck water into their mouths and then push it out through these gills which are located on either side of their mouth. As the water flows out, their gills pick up the oxygen in water, making it possible to breath. Fish breath the same oxygen as humans do, just in a different way.