For your fish to remain healthy they will need proper oxygen. They absorb dissolved oxygen from the water as it passes through their gills. The amount of oxygen in an aquarium is determined by the temperature of the water (cool water holds more oxygen than hot water), and also by the amount of water surface area. Water replenishes its oxygen supply when in contact with the atmosphere. Some persons use an electric pump to force air through a tube into the aquarium. While a small amount of oxygen is absorbed from the air bubbles, the principal purpose of the air-stream is to circulate the water upward to the surface, where oxygen is absorbed.
Since the amount of water surface area determines the amount of oxygen, a round glass bowl that has a lesser circumference at the top should not be filled completely. It should be filled just a little over halfway, to allow for greater water surface area.
Since the amount of water surface area determines the amount of oxygen, a round glass bowl that has a lesser circumference at the top should not be filled completely. It should be filled just a little over halfway, to allow for greater water surface area.