Organisms, like fish, live in water, but still need oxygen to live. Oxygen goes to each cell and helps the fish grow, reproduce, and turn food into energy.

Fish possess specialized structures to carry out the respiratory function, helping them inhale oxygen dissolved in water. Oxygen dissolves in surface water from the aerating action of winds, and also as a byproduct of aquatic plant photosynthesis.

Respiration in fish takes place with the help of gills. Most fish possess gills on either side of their head. Gills are tissues made up of feathery structures called gill filaments providing a large surface area for exchange of gases. Let’s learn more!