10 Beginner-Friendly Aquatic Plants That Grow Without CO2 | Easy-to-Grow Species and Care Tips

Why Aquatic Plant Cultivation Fails and Choosing to Skip CO2

Many people who start growing aquatic plants experience the frustration of plants dying quickly or dissolving away. The main causes of failure are typically three factors: "insufficient light," "insufficient CO2," and "insufficient nutrients." However, setting up CO2 injection equipment right from the start requires significant investment. A complete setup including a regulator, cylinder, and diffuser can easily cost ¥10,000–30,000.

We recommend beginners start with "hardy species that grow even without CO2 injection." These aquatic plants have a strong ability to absorb CO2 from the air directly through water, and their photosynthesis efficiency can be supported by relatively low light levels. Experience the joy of cultivation first, then gradually expand your equipment setup over time. If you're unsure about lighting choices, we also recommend checking out our Complete Guide to Aquatic Plant Tank Lighting for a smoother equipment selection process.

10 Easy-to-Grow Aquatic Plants Without CO2

1. Anacharís (Brazilian Waterweed)

A hardy stem plant that is a staple even in goldfish tanks. It grows well even with low light and is tough against water temperatures ranging from 5–30°C and fluctuations in water quality. Its reproductive vigor is high, and you can propagate it simply by inserting cut stems directly into the substrate. Since growth is rapid, you may need to trim it weekly, but this also makes it easy to feel like you're actively cultivating the plant.

Light Level: Low to Medium / Substrate: Works with either gravel or soil

2. Willow Moss

A classic moss that you attach to driftwood or stones by wrapping with cotton thread. It grows even without CO2 and its densely layered leaves add softness to your tank's overall layout. As it grows, the leaves become dense and create a natural-looking aquascape. It grows most beautifully in cooler water temperatures (20–24°C), so be cautious of high summer temperatures.

Light Level: Low to Medium / Attachment Time: 2–4 weeks

3. Amazon Sword (Echinodorus)

A large rosette-type aquatic plant that becomes the focal point of your tank's background. Since it primarily absorbs nutrients through its roots, pushing solid fertilizer into the substrate significantly improves growth. Leaves can reach 30–50 cm, so it's suited to tanks 60 cm or larger.

Light Level: Medium to High / Note: Leaves may dissolve shortly after planting, but the plant stabilizes once new leaves appear

4. Anubias Nana

A representative shade-loving plant that thrives in dimly lit environments without direct sunlight. The basic approach is to attach it to driftwood or stones without burying the rhizome in the substrate. Growth is extremely slow, but once established, it's easy to maintain long-term. Algae tends to attach to leaves, which is typically managed by combining the plant with algae-eating livestock. For information on pesticide treatment and compatibility, see our Aquatic Plants Safe for Shrimp and Care Guide.

Light Level: Low / Lifespan: Several years or more with proper care

5. Microsorum

A fern-relative that creates a natural-looking aquascape when attached to driftwood. It's extremely hardy and tolerates even some water quality degradation and temperature fluctuations. The underside of leaves develops sporangia from which juvenile plants emerge, making propagation enjoyable. If leaves dissolve, check that water temperature isn't exceeding 28°C.

Light Level: Low to Medium / Ideal Temperature: 18–26°C

6. Vallisneria (Vallisneria spiralis)

Aquatic plant with fine, tape-like leaves that sway beautifully in water flow. It spreads horizontally via runners, creating a natural curtain-like layout when planted in the background. It absorbs nutrients robustly through its roots and pairs excellently with substrate fertilizers.

Light Level: Medium / Propagation: Regularly trim runners to manage growth

7. Ludwigia Palustris

A stem plant with attractive reddish leaves. The reddish coloring intensifies with higher light levels, and it grows well with medium light even without CO2 injection. Adding trace amounts of liquid iron fertilizer enhances coloration.

Light Level: Medium to High / Enhanced Coloration: Add liquid iron supplement

8. Green Rotala

A stem plant with fine, densely packed leaves suited for background planting. With sufficient light, new leaves emerge densely, creating a full, voluminous appearance. Insufficient light causes leaves to thin and stretch, so maintain lighting for 8–10 hours daily.

Light Level: Medium to High / Lighting Duration: 8+ hours recommended

9. Hair Grass (Eleocharis acicularis)

A fine, grass-like carpet plant that creates a turf-like aquascape when planted in the foreground. It's possible to grow it without CO2, though growth is slower; repeated trimming creates a dense carpet. It pairs particularly well with nutrient-rich soil substrates.

Light Level: Medium to High / Substrate: Nutrient-rich soil recommended

10. Pygmy Chain Sword (Sagittaria subulata)

A small foreground plant that spreads via runners, with the same hardiness as Anacharís. It grows to only 5–10 cm in height, making it ideal for foreground to midground planting. Medium light is sufficient, and it's easy for beginners to manage. For easy propagation, see our How to Use Tissue-Cultured Aquatic Plants to reduce disease and snail contamination risks while securing plants.

Light Level: Medium / Propagation: Spreads naturally via runners

Key Management Tips for Success

When growing without CO2, balance in other factors becomes even more important.

Maintain 8–10 hours of lighting daily: Too little causes insufficient photosynthesis; too much leads to rampant algae growth. Using an automated timer outlet is ideal.

Use liquid fertilizer sparingly: In a CO2-free environment, aquatic plant metabolism is slower, so excess fertilizer becomes a source of algae. Start with about half the recommended dose and adjust based on observation.

Don't skip water changes: The standard is a weekly water change of about one-third of the tank volume. This removes waste while also supplying fresh trace elements from fresh water.

Be cautious of summer temperature rises: CO2-free tanks are especially prone to leaf dissolution and algae blooms during hot periods. We've compiled solutions in Aquatic Plant Summer Care | How to Prevent Dissolution and Algae from High Temperatures, so it's reassuring to read it early in summer before the heat peaks.

Plant correctly: Bury stem plants 2–3 cm at the base into the substrate, and for rosette types, bury only the roots while keeping the rhizome above the substrate. This is key to success.

Recommended Plant Combinations

For beginners, we especially recommend combining Anacharís (background) + Willow Moss (on driftwood) + Anubias Nana (midground). This combination offers low demands for light and care difficulty, creating an attractive layout even in a 60 cm tank.

Once you gain confidence in aquatic plant cultivation, adding red-toned plants like Green Rotala or Ludwigia Palustris will greatly expand your layout possibilities. Consider investing in CO2 injection equipment at that point as well. Remember, the key to enjoying aquatic plant cultivation long-term is to build up successful experiences of keeping your plants alive.