Breathing Under Water

Gills in fish help them to use oxygen dissolved in water. Gills are projections of the skin. Gills help in breathing. Gills are well supplied with blood vessels for exchange of gases. But breathing in water is quite difficult as water is dense and having less dissolved oxygen than air.

Breathing under water

The fishes breathe by taking in water through its mouth and sending it over the gills. The oxygen dissolved in the water is extracted by the gills and the extracted oxygen is absorbed by the blood. This oxygen is then carried to all the parts of fishes for respiration.