top of page

The Best Aquarium Plants that thriving Without CO2, with a Little Help from Aquasoil.

When it comes to creating a stunning and vibrant aquarium, live aquatic plants can be a game-changer. They not only enhance the visual appeal of your tank but also contribute to a healthier aquatic environment for your fish and the biological cycle as a whole. While many planted aquarium enthusiasts use CO2 injection to promote plant growth, there is a thriving world of aquarium plants that can flourish without the addition of CO2, as long as you provide them with the right substrate, such as Aquasoil. In this blog, we'll explore the best plants for an aquarium that don't require CO2 but thrive with the support of Aquasoil. But remember that RED colouration are heavily dependant on sufficient CO2 levels that can only be achieved with the addition of extra CO2.

BUT how does these plants survive without the addition of CO2?

In a natural aquarium setup, several factors can introduce and influence the levels of carbon dioxide (CO2) without the need for artificial CO2 injection systems. These factors include:

Fish Respiration: Fish and other aquatic organisms respire, releasing carbon dioxide into the water as a byproduct of their metabolism. The more fish you have in your aquarium, the higher the CO2 production. However, this source alone typically doesn't provide enough CO2 to support high-demanding plants.

Decomposition: Organic matter, such as fish waste, uneaten food, and decaying plant material, contributes to CO2 production as it breaks down in the aquarium. This can be a significant source of CO2 in some setups, particularly in tanks with a lot of detritus.

Substrate: The type of substrate you use can affect CO2 levels. Aquasoil, for example, can release some carbon dioxide into the water as it decomposes. Additionally, certain substrates can promote the growth of beneficial bacteria, which can produce CO2 as they break down organic matter.

Aeration and Surface Agitation: Maintaining proper aeration and surface agitation in your aquarium can help exchange gases with the atmosphere. When the water's surface is in contact with the air, CO2 is naturally exchanged for oxygen. If you have a heavily planted tank, it's essential to strike a balance between aeration and CO2 retention, as excessive surface agitation can lead to CO2 loss.

Biological Processes: The nitrogen cycle and other biological processes in the aquarium involve the breakdown of organic compounds, which can release CO2 as a byproduct.

Plants: During the daytime, aquatic plants use photosynthesis to absorb CO2 from the water and release oxygen. They contribute to maintaining a balanced CO2 level in the aquarium. However, at night, plants reverse this process and respire, releasing some CO2. The net effect depends on the balance between plant growth and respiration.

Carbonate Hardness (KH): The KH of your aquarium water can influence CO2 levels. A lower KH value allows for easier fluctuations in CO2 levels, as there are fewer buffering compounds to stabilize pH. However, it's crucial to monitor KH and pH to prevent rapid pH swings that can harm your fish.

It's important to note that in heavily planted aquariums with high-light and high-demanding plants, the natural introduction of CO2 might not be sufficient to meet plant requirements. In such cases, hobbyists often turn to CO2 injection systems to ensure optimal plant growth.

To maintain a stable and healthy environment in your aquarium, it's essential to monitor CO2 levels, pH, and other water parameters regularly. Adjustments to lighting, water movement, and CO2 supplementation may be necessary, depending on your specific goals and the needs of your aquatic plants and fish.

Before diving into the list of plants, let's understand why Aquasoil is an essential factor in a CO2-free planted aquarium. Aquasoil is a specialized substrate designed for planted tanks. It provides several benefits:

Nutrient-Rich: Aquasoil contains essential nutrients like nitrogen, phosphorus, and potassium, which are crucial for plant growth. These nutrients are released slowly over time, ensuring that your plants have a consistent supply of what they need.

Buffering Capacity: Aquasoil can help stabilize water parameters, particularly the pH level. This is crucial because fluctuations in pH can stress your aquatic plants.

Anchoring Roots: The texture of Aquasoil allows plant roots to anchor firmly, ensuring stability and preventing uprooting.

If you do not use an Aquasoil you have to do water column liquid fertiliser and root tablets as a minimum.

REMEMBER your aquarium plants need 3 legs to be healthy – Food – Lighting – CO2 in some form or another.

Plant species:

Now, let's delve into some of the best aquarium plants that thrive in a CO2-free environment when paired with Aquasoil:

Epiphytes do not even need the Aquasoil:

Then there are plants that take up most of their food from their roots so Aquasoil or the addition of root tabs are essential for optimum growth:

Amazone swords (Echinodorus)

Then most stem plants will grow well but will not show red colouration without extra CO2:







Pogostemon - etc.

“Cuba” Micranthemum sp.

“MM” Micranthemum micranthemoides

Marsilea hirsute

Microcarpaea minima merrill

Others: Hydrocotyle

Rorippa aquatica


Tiger lotus


Juncus repens

Remember that while these plants don't demand CO2 injection, they still require adequate lighting, feeding, water circulation and regular maintenance to thrive. Prune them when needed, remove any dead or decaying leaves, and monitor water quality closely.

In conclusion, creating a lush and thriving planted aquarium without CO2 is entirely possible when you choose the right plants and provide them with a nutrient-rich substrate like Aquasoil. By selecting plants that are well-suited to this environment, you can enjoy the beauty and benefits of a planted tank with less complexity and expense. Happy aquascaping! 🌱🐟

388 views0 comments

Recent Posts

See All


bottom of page