Last Updated on November 6, 2021 by Marco C.
No matter what the setup for your aquaponics system, your fish tank will need air. This article will tell you everything you need to know about how to aerate a fish tank without a pump.
Just like humans, fish need air to provide crucial body functions. In a closed setting like a tank, there often is not enough natural air provided to keep the ecosystem thriving. Many people use an air pump to give extra oxygen to their system.
However, if you do not want to use an air pump there are some special things you can do to ensure your fishies receive enough Oxygen. It’s important to understand the critical function oxygen plays in a fishes’ life.
What Does Oxygen Do For My Fish?
Oxygen is one of the most important things for fish because they require it in order for their cells to go through aerobic respiration. Basically, this means they use it for breathing. Just like humans, fish need to breathe in O2 and exhale CO2.
Breathing gives the fish all the energy they need to move around and live. According to the Iowa Department of Natural Resources, air does not enter through fishes’ nose and mouth. Unlike humans, oxygen enters through the gills first then enters the bloodstream.
Fish take in water through their mouth and move it into their gills.
The gills are organs located behind the head of the fish. This fascinating organ is filled with many small blood vessels which enable oxygen to pass through and carbon dioxide to exit.
Oxygen in the air is not an adequate source for fish. This is why they cannot breathe above water. Instead, they receive their air from Dissolved Oxygen (DO) – which means oxygen gas which is dissolved in water.
The amount of DO present in your tank depends on the conditions. You need to ensure that there is enough oxygen available for your fish. You can test the DO levels by using a purchased test kit.
When testing you are looking for a level of at least 5 mg/L. However, the optimum range is 8mg/l. As long as that is maintained, your fish will be happy. If you decide to bypass the use of an air pump there are other ways to oxygenate your water.
How To Oxygenate A Fish Tank Without A Pump
The best place to understand how to oxygenate water is nature itself. In nature, there are two main sources of oxygen.
The first one is our reliable friend, plants! Putting plants into your fish tank is the first step people should take if they want to aerate their fish tank without a pump.
Just as they do above the water, plants emit oxygen Oxygen and absorb Carbon Dioxide underwater. If you fill your system with enough aquatic plants and keep the ecosystem balanced, it is possible to generate enough oxygen so that you don’t need an air pump.
There are certain varieties of plants that give off more oxygen than others. Some easy picks are the Java Fern, Anubias, or the Dwarf Hairgrass. Make sure you secure the roots to ensure its survival after planting.
Don’t forget that plants require a certain amount of light. Check each plant’s requirements before making your decision.
Oxygen is given off wherever the leaves are located. This means if you want to oxygenate your water at all points in the fish tank, put plants at the top, middle, and bottom of your tank. A good option for oxygenating the bottom is to use carpet plants such as Micranthemum.
A Second Option On How To Aerate The Water
There is actually a difference between ‘oxygenation’ and ‘aeration’. Oxygenation refers to the actual gas being put into the water. Aeration has to do with the physical movement of the water. When water moves, it creates oxygen-filled bubbles which enter the water.
If you want to aerate your fish tank without a pump, you can have a filter system where you can control the flow rate. The sucking of water will create bubbles.
After it drops through the filter it will return into your system. When this water hits the surface, it is creating oxygen.
Learn more about: How To Make A Venturi Water Pump For Aquaponics
Be careful to not create too high of water pressure – this may disturb your fish. Every kind of fish requires a different atmosphere so do your research carefully before making your decisions.
Another way is to create a filter which makes contact with a large surface area of your tank water. You can do this by creating a filter with many drainage holes. For example, your filter can drain out at multiple points spanning half of your tank.
Also, you can use a waterfall filter which drops water deeper into your tank. The tall height of the water causes more aeration. The higher you set your filter, the more oxygenation is created.
Lastly, you can buy a special attachment to your filter’s output which is made to increase aeration of the filtered watering re-entering the tank. This is called a Lily Pipe and can be purchased from most aquarium stores.
Final Design Tips
We recommend carefully thinking about all your design points before making any purchases. The design of the tank heavily affects what is needed.
In the case of how to aerate a fish tank without a pump, the size of your tank matters. This is because the larger the surface area of your tank water the more potential oxygen from the air can hit your water.
If you truly want to aerate your fish tank without a pump, the best shape of tank to get is a wide and shallow one. Start with the tank shape and size and add in everything else we suggested.
If you pay attention and avoid overcrowding your tank with fish, you can maintain an adequate amount of oxygen in your tank. While all this is possible, keep in mind it is more work.
If you want to learn more about air pumps check out our other article about it!
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