HomeWhy is it necessary to maintain a healthy aquarium? What is a chemical environment? Why does an aquarium need a good source of oxygen?

Why does an aquarium need a good source of oxygen?
      Oxygen is used by fish to provide energy. Fish cannot breathe oxygen from the air like people. They breathe the oxygen dissolved in the water. Oxygen is brought into the aquarium system largely through air pumps and also by plants.

Why is an air pump needed?
How do plants provide oxygen?