Nighttime Aeration in Aquariums: Why It's Crucial for Fish Health

 

Aerating a tank at night can be more important than during the daytime due to a few factors:

Temperature

During the daytime, especially in warm climates or when the tank is exposed to direct sunlight, the water temperature tends to rise. Warmer water has a reduced capacity to hold dissolved oxygen compared to cooler water.

The solubility of gases, including oxygen, decreases as temperature increases. This means that as the water temperature rises, the amount of oxygen that can dissolve in the water decreases. The warmer water becomes saturated with less dissolved oxygen, potentially leading to lower oxygen levels in the tank.

By aerating the tank at night, you can help replenish the dissolved oxygen levels that may have been depleted during the day. The aeration process involves increasing the surface area of the water, allowing for greater contact between the water and the air. This promotes gas exchange, where oxygen from the surrounding air can dissolve into the water, increasing the oxygen content.

Aerating the tank at night when the ambient temperature is cooler can help mitigate the decrease in dissolved oxygen caused by the higher water temperature during the day. It ensures that an adequate amount of oxygen is available for the aquatic organisms inhabiting the tank, supporting their respiration and overall health.

Photosynthesis 

In natural aquatic environments such as lakes, rivers, or ponds, there are photosynthetic organisms like algae and aquatic plants. These organisms utilize sunlight to undergo photosynthesis, a process where they convert carbon dioxide and sunlight into energy-rich organic compounds, releasing oxygen as a byproduct. This oxygen produced during photosynthesis helps to maintain higher oxygen levels in the water during the daytime.

However, in an artificial tank or aquarium setting, the presence of photosynthetic organisms may be limited. While some tanks may have live plants that undergo photosynthesis, the level of photosynthetic activity is typically lower compared to natural bodies of water.

As a result, the oxygen production through photosynthesis is reduced during the daytime in artificial tanks. Without a sufficient source of oxygen from photosynthesis, it becomes even more crucial to provide supplemental aeration to ensure adequate oxygen levels for the aquatic inhabitants.

By aerating the tank at night, you help compensate for the lower oxygen production during the day. Aeration increases the surface area of the water, allowing oxygen from the surrounding air to dissolve into the water. This process helps replenish the oxygen levels and creates a more favorable and oxygen-rich environment for the aquatic organisms.

In summary, the second point emphasizes the need for additional aeration in artificial tanks during the night because the natural oxygen production through photosynthesis is typically limited in these environments.

Oxygen consumption 

Fish and other aquatic organisms consume oxygen as they respire, breaking down food and carrying out their metabolic processes. Oxygen demand is relatively constant throughout the day and night. Therefore, by providing additional aeration during the night, you ensure that there is a steady supply of dissolved oxygen available for the aquatic inhabitants, preventing oxygen depletion and promoting their overall well-being.

It's worth noting that the specific requirements for aeration can vary depending on the type of tank, the species of fish or aquatic organisms present, and other factors. It's always advisable to consult specific guidelines for the particular tank or seek advice from experts in the field to ensure optimal conditions for the inhabitants.

Aerating your aquarium is very important because it increases the dissolved oxygen levels, which is very useful for improving the health of the fish in your aquarium. But most hobbyists are not concerned about aerating the tanks at nighttime. Most of them switch off the air pumps at night because of the noise of the air pumps. But aerating the tanks at night is more important than during the day. In this article, I’m trying to discuss this matter briefly.

Figure 1: Aerating the tank

What happens in the aquariums at night?

We know all living animals need oxygen. At nighttime, not only fish and other living animals consume dissolved oxygen (DO) in the water but also all living plants, some tiny organisms (ex: bacteria), and even algae consume the DO in the water. Therefore, oxygen consumption at night is higher than in daytime.

Not only that, but oxygen production also goes down at night than in daytime because all the plants will not produce oxygen at nighttime. Therefore, DO levels in the water decrease very fast in the aquarium in the nighttime.  The diagram below shows what happens to dissolved oxygen levels in the aquarium within 24 hours.

Figure 2: How dissolved oxygen levels changed with in 24 hours in an aquarium.

Therefore, we must aerate the tank to increase the DO levels in the middle of the night than in the daytime. The DO levels of 2 am to 6 am are deficient, and time durations can be changed based on the fish density and availability of plants in the aquarium.

Simple Solutions

     Solution 1 - Switch on the oxygen pump at the night

If you do this, DO levels will increase in the water, and also it helps to balance the temperature in the aquarium.

 

Solution 2 - Introducing an aquarium light

Plants will produce oxygen at night if you provide light artificially by an aquarium light.

These are the simple solutions you can follow to overcome this issue.

Note

Aerating the tank and switching on the light 24/7 might increase the stress on the fish due to the noise and sharp light. Therefore, it is better to switch off the light and the air pump for a few hours in the daytime, which will help keep a healthy aquarium.