Skip to Content

What Does CO2 Do for Aquarium Plants? Is It Necessary?

get 5 secrets to thriving plants

If you have an aquarium with live plants, you may have heard about the importance of CO2 for plant growth. But what exactly does it do? And is it really necessary for successful aquarium plant growth? 

Carbon dioxide, or CO2, is essential for most aquarium plants to grow. CO2 is necessary for photosynthesis, can help aquarium plants grow faster than average, and can significantly improve the overall health of your tank. However, it is not essential for all aquarium plants. 

In this blog post, we’ll explore the role of CO2 in an aquarium environment and answer whether it is necessary for healthy plant growth and more! 

CO2 is Essential for Photosynthesis

Photosynthesis turns light energy from the sun into chemical energy plants use for food. During this process, carbon dioxide (CO2) is absorbed from the water, and oxygen is released. 

With good CO2, photosynthesis will occur, and the growth rate of aquatic plants will be dramatically reduced. 

Additionally, with a proper supply of CO2, an aquarium’s nitrogen cycle can be turned on balance, leading to an unhealthy tank. 

Co2 diffuser aquarium

CO2 is arguably the most essential element in the planted aquarium. It is required for respiration and growth by all aquatic plants, used in photosynthesis. 

Plants need a constant supply of CO2 during light hours; otherwise, they can suffer. 

Additionally, the nitrogen cycle in your aquarium relies on the availability of CO2 for nitrate production. 

With an adequate supply of CO2, nitrate levels will remain stable, allowing for a healthy environment for your fish and plants.

CO2 Helps Aquarium Plants Grow Faster

CO2 is essential for photosynthesis and plays a vital role in the growth rate of aquarium plants. 

With the addition of CO2, the growth rate of plants can be increased significantly. In a high-tech setup, it typically takes 2-4 months for the plants to be fully established, and the tank can finally be considered mature. 

However, with the addition of CO2, this process can be shortened significantly. For example, Anubias in a non-CO2 supplemented tank will take three weeks to one month plus and sometimes even longer, before a new leaf will start growing. 

With CO2 supplementation, Anubias will grow a leaf every three weeks. It does not skip. 

Increasing lighting, nutrients, and CO2 levels can help plants, such as Pearlweed, grow about 2 centimeters weekly. 

In conclusion, adding CO2 can help aquarium plants grow faster and more efficiently. 

To summarize, the most effective way to make plants grow faster in a new tank is to increase lighting, nutrients, and CO2 levels. 

This will ensure that the plants have all the resources they need to grow at a faster rate. Dialing in the perfect balance may take some time, but it can be done with some patience and experimentation.

CO2 Can Improve the Overall Health of your Aquarium

CO2 is a significant part of the photosynthesis equation. It has a direct link with the energy production of plants, and it can significantly affect the health of an aquarium.

When the plants have access to the correct amount of CO2, they can grow better and faster. 

This will lead to an increased presence of oxygen in the water, helping to maintain an optimum balance between oxygen and carbon dioxide. 

A balanced aquarium will have a higher pH level, meaning the water will be less acidic, leading to a healthier environment for the fish.

In addition, when CO2 is available to the plants, they will be more resilient to diseases and parasites, as they can grow faster. 

Finally, CO2 can also help to maintain a better balance of nutrients in the water. This means that there will be less likelihood of algae growth, as the plants will be able to absorb more of the nutrients that would otherwise contribute to algae blooms.

Some Plants Don’t Need CO2

While CO2 is an essential nutrient for aquarium plants, some species actually do not require it to grow and thrive. 

Low-tech tanks are designed for plants that don’t need additional CO2 supplementation. This is ideal for hobbyists who are new to the aquarium scene and don’t have the knowledge or equipment to monitor and manage the levels of CO2 in their tanks. 

Plants such as Anubias, Java Fern, and Java Moss, among others, can thrive without additional CO2 injection. 

These species are slow-growing and less demanding in terms of water parameters and lighting intensity. 

They require only essential nutrient supplementation, making them ideal for beginners or those who simply don’t want to invest in the necessary equipment for a high-tech tank. 

For those looking to build a low-tech tank, these species of plants will give a beautiful aquascape with minimal effort. 

With the right combination of light, nutrients, and CO2 (or lack thereof), you can create a lush and healthy aquarium environment that will last for years. 

That is why hobbyists need to pay attention to water parameters, especially pH and CO2. The right amount of CO2 will give a good balance between the other nutrients in the water, nitrogen, and phosphorus. 

Too much CO2 and too little of the other nutrients will starve the plants, even if the CO2 is within the correct parameters. 

On the other hand, too little CO2 and too many other nutrients will also be a problem, as the plants will need more CO2 for proper photosynthesis. 

Proper balance is the key to a successful aquascape, and CO2 is just one of the factors that need to be taken into consideration.

How to Add CO2 Naturally to Your Tank 

1. Add fish and invertebrates: Fish and invertebrates, like shrimp and snails, are great for naturally adding CO2 to your tank. 

As they breathe, they will produce CO2, which the plants will then use.

2. Use a soil substrate: Using a soil substrate with organic matter will create an environment in which CO2 can be released over time naturally. 

3. Utilize decomposing plant material: Decomposing plant material like leaves, mosses, and grasses can provide natural CO2 for your tank. 

Just make sure to remove any decaying material from the tank if it starts to get out of control.

4. Make use of driftwood: Driftwood contains tannins, which can help raise the pH levels of your tank and also produce CO2 as it breaks down.

5. Invest in a carbon dioxide diffuser: A CO2 diffuser is one of the most efficient ways to add CO2 to your aquarium as it continuously pumps small amounts into the water. 

However, this should only be used if you have an established tank, as it’s easy to overdose on CO2 if you’re not careful.

6. Decomposing Plant Material: Plant matter is an excellent source of CO2, and aquarium owners can benefit from adding decomposing plants like leaves, mosses, and grasses. 

As the plants break down, they will release CO2 into the tank. 

It’s essential to keep an eye on the amount of organic material in your tank, as it can quickly get out of control and damage the ecosystem.

Aquarium Plants That Do Not Need CO2

As mentioned, some aquarium plants do not require CO2 in their environments. Below is a quick list of aquarium plants that do not typically need CO2: 

  1. Anubias
  2. Java Fern
  3. Cryptocoryne
  4. Java Moss
  5. Bucephalandra
get 5 secrets to thriving plants