Oxygen Importance For Fish

One of the most interesting hobbies and one that attracts young and old alike is Aquarium keeping

The Way Fishes Breathe

Though fishes are submerged they require oxygen for breathing and this they get by means of passing the water through a special organ called gill. The gills absorb the dissolved oxygen in the water and pass it to the blood vessels. The Gills are the lungs of the fish. The Gills also excrete carbon-di-oxide produced by the fish body. In nature where the water either is available in a large volume or is flowing continuously there is no problem. Oxygen in water depends on the surface area available for the water to adsorb the oxygen available in the air. If the movement of water surface is more, then there is more adsorption of oxygen into the water, as the moving water surface always takes the oxygen rich water to the bottom and less oxygen rich water to the top. Also the movement upward enables the gases such as dissolved carbon-di-oxide to escape into the air thus paving way for more oxygen adsorption. One should remember this simple water chemistry. This is the reason the flowing waters of nature are always fresh and rich in oxygen than the stagnant waters.

Functions of Water Plants

Water plants also produce carbon dioxide. They consume oxygen too. Fortunately they consume carbon dioxide when light is available and release oxygen as a result of photosynthesis. The process is reversed at night. Plants also absorb nitrogen rich matter released by fishes from water to generate necessary energy. This means the presence of plants releases additional oxygen into the water which is very essential for aquatic life forms and also absorbs the wastes created by fish and other forms of aquatic life. There are also microscopic organisms in water which also consume oxygen. But their presence is always limited by other factors. If there is an upset to the factors that limit the presence of microscopic organisms called bacteria then there is an outbreak of bacterial growth, resulting in excess oxygen consumption and cloudiness of water. There are good bacteria and bad bacteria. The good bacteria helps in breaking down the nitrogenous waste into more acceptable nitrates which can then be absorbed by the plants. The absence of good bacteria would result in nitrite build up and also encourage an outbreak of bad bacteria. Remember Nitrate and Nitrite are different.