Here at Pond Planet we know how vital oxygen is to all aquatic inhabitants whether they are Koi, goldfish, tropical / marine fish or bacteria.
Fish, plants, decaying matter and other aquatic inhabitants all consume this vital source of life.
Aquatic plants produce oxygen as a by-product of photosynthesis. The rate of photosynthesis is dependent upon light levels which means the amount of oxygen in a pond fluctuates daily. Oxygen levels are usually at their highest at midday and lowest just before sunrise.
Oxygen depletion in a pond is the result of demand exceeding supply. During the summer months this is more likely to occur as warm water contains less oxygen than cold water.
Therefore fish losses usually occur on an evening during warm weather months. Other factors such as overstocking, overfeeding and chemical treatments all have an impact on oxygen levels within the pond and increase the chance of fish losses.