Having enough oxygen in your aquarium is one of those things people often take for granted, but it’s so vital to your fish’s health. How can you make sure your fish is getting enough air? Typically, the most obvious signs of oxygen deprivation in fish include lots of resting at the bottom of the tank, a lack of appetite, and rapidly moving gills. In a worst-case scenario, your fish may start gasping for air at the surface of the water, which means it’s definitely time to take action!
The first step is to do a large water change, which will immediately infuse the tank with fresh oxygen. If the fish immediately perk up, the second step is to determine why the aquarium was suffering from lack of oxygen. Common causes include high water temperatures, too many fish in the tank, certain medications or chemical treatments, and not enough water surface agitation.
You can directly measure the dissolved oxygen content using a water test kit or digital meter. Ideally, the oxygen content in a freshwater fish tank should be around 7 to 8 ppm (or mg/L). To figure out the best kind of setup for increasing oxygen in your aquarium, we ran several experiments using a dissolved oxygen meter and here’s what we discovered:
The experiment results for increasing dissolved oxygen in different aquarium setups
Note: Powerheads and circulation pumps were also tested, but the exact results were not recorded. The venturi-type powerhead did not perform as well as the powerhead pointed towards the top of the tank that created surface agitation. A circulation pump was also tested, but it did not improve the oxygen content significantly.
Based on our experiments, we definitely see that increasing gas exchange at the water surface has a positive impact on oxygen content. Gas exchange in aquariums is the process in which carbon dioxide from the water (a waste product produced by your fish) exits into the air and new oxygen from the air is dissolved into the water. Given this information, here are three proven ways to increase oxygenation in your aquarium:
Too many floating plants can greatly reduce oxygen levels in your fish tank.
Adding an air source to your fish tank is very easy – all you need is an air pump to push air into the water, airline tubing for the air to travel through, and a check valve to prevent water from flowing into the tubing.
How to attach an air pump in an aquarium
Those three components reside outside of the aquarium, but the last bit of airline tubing (on the left-hand side) enters the water. From there, there are several types of attachments you can connect to the airline tubing inside the aquarium.
Add more air to your aquarium using an air stone, sponge filter, or moving bed filter.
All these methods of adding air to your fish tank promote excellent surface agitation and oxygenation of water, providing an ideal, stress-free environment for your fish to live in.