Do fish breathe

Answer 1

They extract oxygen from the water using gills. Pumping water through the gills is called respiration, and is basically like breathing. So yes, fish breathe, they just don't usually breathe air.

Some fish however, such as the lung fish, breathe (gulp) air from the surface.

Fish breathe through organs called "gills" which are located on both sides of their heads. Gills are just like the lungs of land animals, but adapted slightly to enable the fish to breathe underwater.

Fish breathe by gulping water. The water brushes over the gills of the fish. The gills then extract the oxygen out of the water and replace it for carbon dioxide. Then the water passes out of the slits/gills on the side of the fishes head.

Gills are very effective at their jobs. They can extract 80% of the waters oxygen in every gulp.

Gills are specifically evolved uniquely for the species of the actual fish. For example, a saltwater/ocean fish needs stronger gills to extract oxygen from the harsh, salty water. Whereas freshwater/river fish have less stronger gills, because they don't have an issue with salty water. This is also why Freshwater Fish cannot survive in the ocean.