CO2 Aqarium Kits, Systems & Accessories

Yes, you can add CO2 to your aquarium. When added properly, CO2 shouldn’t harm your fish or your plants and provides benefits like slowing algae growth and reducing the pH for fish that need soft water. Keep in mind that you may not be able to add as many fish if you’re using a CO2 aquarium kit. Fish produce CO2 naturally, and the more fish you have, the more CO2 will already be in your tank. Learn more about water conditions in our guide on How to Take Care of Freshwater Aquatic Life: Tips for New Fish Parents.

In an aquarium, CO2 injection is the process of adding carbon dioxide to the water. It can be done in several different ways, but the most common method is to use a pressurized CO2 injection kit for an aquarium, which mixes the CO2 directly into the water column. They’re typically used for planted aquariums, and habitats that use CO2 injection are often referred to as “high-tech.”

Whether or not you need an aquarium CO2 system for your plants depends on your setup. CO2 does occur naturally in most aquariums, as it is produced by your fish when they breathe, so small planted aquariums may not need more. However, in larger planted aquariums or those with high lighting levels, the natural CO2 may not be enough. CO2 can also help you grow brighter and more dense vegetation in your aquarium. The amount of CO2 you’ll need depends on the size of your tank as well as the fish and plants you keep.