Submerged Aquarium Plants as Nitrate Suppressors

Submerged Aquarium Plants as Nitrate Suppressors

In the pursuit of a balanced aquatic ecosystem, the significance of submerged aquatic plants stands as a hidden gem. Often overshadowed by their floating or partially emerged counterparts, some underwater plants also contribute a lot by addressing the challenge of nitrate buildup.

Hornwort, Vallisneria, and some other fast-growing plants have evolved to thrive beneath the water’s surface. They are true experts at absorbing nitrates and other nutrients, helping maintain a balanced and healthy environment for your fish and other aquatic animals.

Some aquarists prefer not to utilize floating plants, either due to aesthetic concerns or other reasons. As a result, in this article, I will be exclusively talking about submerged aquatic plants that are easy to care for.

List of submerged plants

  1. Vallisneria
  2. Hornwort
  3. Elodea canadensis
  4. Pogostemon octopus
  5. Anacharis 
  6. Pearlweed 
  7. Hygrophila angustifolia
  8. Dwarf sagittaria
  9. Red tiger lotus
  10. Ludwigia repens
It is very important to understand that lighting plays one of the most important parts here. In the case of insufficient light, the plants will not grow as fast as they can.

Therefore, their nitrate consumption will be minimal and sluggish, as their uptake will be constrained by the intensity of the lighting.

1. Vallisneria

Vallisneria Care Guide – Planting, Growing, and PropagationVallisneria sp., commonly known as Vallisneria or Vallis, is a genus of aquatic plants belonging to the Hydrocharitaceae family. Depending on the species, it can range from 10 inches up to 3 ft. (25 – 100 cm) in length.

These plants are popular choices in aquariums for their aesthetic appeal and ability to absorb nutrients and harmful chemicals, including nitrates, from the water. This makes it a valuable addition to maintaining water quality in aquariums.

Vallisneria can create a lush underwater landscape while also contributing to a healthier aquatic environment.

Vallisneria features include:

  • Long, ribbon-like leaves for an elegant appearance.
  • Various sizes to suit different tank dimensions.
  • Ideal as background plants, adding depth to aquariums.
  • Rooted in the substrate.
  • It will grow in anything including plain gravel or sand.
  • Runner formation allows natural propagation.
  • Aids in algae control by competing for nutrients.
  • Contributes to water oxygenation through photosynthesis.
  • Can grow in brackish water.
  • It can grow even in low-light planted tanks.

Basic Requirements:

Vallisneria plants are truly remarkable. They can thrive in both freshwater and brackish water environments, showcasing their undemanding nature and versatility.

  • Water pH: 6.5 – 8.0.
  • Hardness: Soft to hard water.
  • Temperature: 68 – 82°F (20 – 28°C).
  • Lighting: Moderate.

Care level: Easy.

Propagation: by runners.

Vallisneria
PROS CONS
Beautiful and decorative. Does not like acidic water
Hardy. Not for nano tanks
Easy to care for and maintain.  
Can grow in any substrate.  
Easy to propagate.  

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2. Hornwort 

Hornwort (Ceratophyllum demersum)Hornwort (Ceratophyllum demersum) is a very popular aquatic plant known for its unique features and versatility. With its fine, feathery foliage, Hornwort adds a touch of natural elegance to aquariums.

Hornwort possesses a rapid growth rate and impressive height. In the wild, it can grow up to 2 ft (2 m). Given favorable conditions, this plant can achieve growth of 0.4 to 0.8 inches (1 – 2 cm) per day.

For example, according to the experiments, Hornwort reduced ammonium and nitrate by more than 62% and 41.66% in 6 – 18 days. 

Hornwort features include:

  • Green to yellowish coloration.
  • Needle-like filamentous leaves borne on tall, slender stems.
  • The plant lacks true roots.
  • This plant does not need the substrate.

Basic Requirements:

One of the distinctive qualities of Hornwort is its adaptable nature. It can thrive in a wide range of water parameters, including varying levels of light and temperatures.

  • Water pH: 6.0 – 8.0
  • Hardness: Soft to hard water
  • Temperature: 64 – 86 °F (18 – 30°C)
  • Lighting: Moderate

Care level: Easy.

Propagation: by cutting or side shoots.

Hornwort
PROS CONS
 A very beautiful plant. Brittle leaves. Needles break off very easily.
Fast growth rate. Can be a super hardy plant or die almost immediately.
Easy to care for and maintain.  Not for nano tanks
It has heavy metal absorption properties!  
This plant is amazing at reducing nitrates.  
It will also help to clear the cloudy water in the tank!  

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3. Elodea canadensis

Elodea Сanadensis Care Guide – Planting, Growing, and PropagationElodea canadensis is a widely recognized aquatic plant for its fast growth rate. This plant exhibits slow growth even at 40°F (4°C) and is able to survive inside ice for some time.

Due to its ability to establish itself quickly in nature, this plant has also earned the nickname “Water plague, or Water pest”. In the wild, it can attain a massive height of up to 6 ft (2 m). In aquariums, this plant usually features a height of 10 – 20 inches (20 – 50 cm).

Elodea canadensis is adaptable to various lighting conditions. Its hardy nature makes it perfect for beginners, as it can withstand changes in water parameters.

Elodea canadensis features include:

  • Stem plant with densely packed leaves.
  • Can grow in any substrate.
  • The stronger the light, the faster the growth.
  • The leaves can range in shape.

BasicRequirements:

  • Water pH: 6.5 – 9.0
  • Hardness: Soft to hard water
  • Temperature: 50 – 77°F (10 – 25°C)
  • Lighting: Moderate – high

 Care level: Easy.

Propagation: by cutting or side shoots.

Elodea canadensis
PROS CONS
Aesthetic appeal In very high concentrations, the juice of Elodea canadensis can be poisonous to aquatic life
Fast growth rate. Not for nano tanks
Easy to care for and propagate.  
Great at reducing nitrates.  
Elodea canadensis reduces the growth of algae  
Elodea provides hiding spots and breeding areas for small fish and invertebrates  

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4. Pogostemon Octopus

Pogostemon Octopus (quadrifolius, stellatus ) Care Guide – Planting, Growing, and PropagationPogostemon octopus (Pogostemon quadrifolius) is a perennial aquatic stem plant (average 10 – 20 inches or 25 to 50 cm tall) characterized by long, wispy foliage that is bright green.

Under favorable conditions, the plant’s stems take about 2 – 3 weeks after planting to attain giant sizes and grow to the water surface.

Pogostemon octopus can be grown in emersed or submerged environments which makes this plant a great choice for paludarium setups as well.

Pogostemon octopus features include:

  • Thick stems and very long narrow leaves.
  • Can be grown in emersed or submerged environments.
  • Can grow in any substrate.

Basic Requirements:

  • Water pH: 6.5 – 7.5.
  • Hardness: Soft to hard water.
  • Temperature: 75 – 82 °F (23 – 28 °С).
  • Lighting: Moderate.

Care level: Easy.

Propagation: by cutting.

Pogostemon octopus

PROS CONS
 The plant looks very airy, elegant, and beautiful Not for nano tanks
Fast growth rate.  
Easy to care for and propagate.  
Great at reducing nitrates.  
A great choice for paludarium setups  

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5. Anacharis

Anacharis (Egeria densa) Care Guide – Planting, Growing, and PropagationAnacharis (Egeria densa), also known as Brazilian waterweed, is a versatile aquatic plant that is popular among aquarium hobbyists and water garden enthusiasts.

This is a very good plant for beginners, and its rapid growth can remove nitrates in the aquarium from the start.

In nature, this aquatic plant can reach 6 ft (2 m) or more in length. In aquariums, Anacharis can easily double or triple in size just in one month and provide lots of shade and shelter for fish and invertebrates.

Anacharis features include:

  • Feathery appearance.
  • Beautiful light to bright green leaves.
  • Branching stems covered in bunches of linear, whorled leaves.
  • Thick, long, green stems.
  • Dense growth.
  • Can grow in any substrate.

Basic Requirements:

Anacharis is a hardy plant that can tolerate a wide range of water parameters, including pH, temperature, water hardness, and even slightly brackish conditions.

  • Water pH: 6.0 – 8.0.
  • Hardness: Soft to hard water.
  • Temperature: 59 – 82 °F (15 – 28 °C).
  • Lighting: Moderate to High.

Care level: Easy.

Propagation: by cutting.

Anacharis

PROS CONS
 The plant looks very airy, elegant, and beautiful Not for nano tanks
Fast growth rate.  
Easy to care for and propagate.  
Great at reducing nitrates.  
Tolerates very low temperatures  
Prevents algae growth  

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6. Pearlweed 

Pearlweed (Hemianthus micranthemoides or Hemiánthus glomerátus) Care Guide – Planting, Growing, and PropagationPearlweed (Hemianthus sp.) is probably one of the most versatile plants in the hobby. Due to its appearance, this plant is commonly used in aquascaping and aquarium design.

It can be grown as a foreground, mid-ground, background, float, or even as a terrestrial form depending on the aquarium’s size and conditions. Even more, whether in a low-tech tank or a high-tech tank, Pearlweed will thrive, and this bright green plant does an excellent job at absorbing nitrates.

When optimal conditions are met, Pearlweed will grow so fast that you will have to cut it back weekly. Under high lighting, this plant can make a small tank carpet in 2-3 months.

Pearlweed  features include:

  • Small, ovate, narrow, bright green leaves.
  • Delicate, thin green stem.
  • Creates carpet under high lighting.
  • Can grow in any substrate, left floating, or even tied to driftwood.

Basic Requirements:

  • pH: 5 – 7.5
  • Water Hardness: Soft to hard water.
  • Temperature tolerance: 66 – 82 °F (19 – 28 °C).
  • Lighting: Moderate to high. 

Care level: Easy.

Propagation: by cutting.

Pearlweed

PROS CONS
Versatile plant Can melt if there is not enough nitrogen.
Fast growth rate. Hard to plant.
Easy to care for and propagate.  
Great at reducing nitrates.  
Can be used in nano tanks  

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7. Hygrophila angustifolia

Hygrophila angustifolia careHygrophila angustifolia is a fantastic choice for any aquarium. With its rapid growth and gracefully elongated leaves (up to 10 – 20 inches or 25 – 50 cm), this plant is also incredibly undemanding when it comes to care.

It can thrive in any substrate, without the need for fertilization, tolerates shaded areas, can be grown both submerged and partially emerged, and readily adjusts to a wide range of conditions.

Due to its rapid growth, Hygrophila angustifolia functions like a natural nutrient extractor, efficiently removing nitrates and phosphates from the water.

Hygrophila angustifolia features include:

  • It can grow emersed and submerged.
  • Long and narrow leaves, closely resembling the leaf blades of a weeping willow tree.
  • Reddish brown hues on stem and foliage.
  • Can grow in any substrate or tied to driftwood.

Basic Requirements:

  • pH: 6.5 – 8.0
  • Water Hardness: Soft to hard water.
  • Temperature tolerance: 68 – 82 °F (20 – 28 °C).
  • Lighting: Moderate to high.  

Care level: Easy.

Propagation: by cutting.

Hygrophila angustifolia

PROS CONS
Versatile plant Not for nano tanks.
Fast growth rate. Does not like too soft water
Easy to care for and propagate.  
Great at reducing nitrates.  
A great choice for paludarium setups.  

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8. Dwarf Sagittaria

Dwarf Sagittaria Care Guide – Planting, Growing, and PropagationDwarf Sagittaria (Sagittaria subulata) is known for its grass-like appearance, ease of care, and its ability to adapt to various aquarium conditions. Additionally, Sagittaria subulata also has some variations.

In nature, Dwarf Sagittaria can be seen growing in marshes, estuaries, and shallow waters (freshwater and brackish) in emersed, and submersed form. It relatively easily tolerates salinity up to 10 ppt (1.0075 SG).

This is a perennial plant species with a height of up to 4 – 6 inches (about 10 – 15 cm). Despite its small size, this plant is a relatively fast grower and can quickly cover the substrate with its runners.

Dwarf Sagittaria features include:

  • Grass-like appearance (thin, elongated leaves that grow in dense clusters).
  • Creates a lush foreground or midground carpeting effect.
  • The leaves can range from light green to slightly darker shades.
  • Rosette plant.
  • Requires nutrient-rich substrates.

Basic requirements:

  • WaterpH: 6.0 – 8.0.
  • Hardness: Soft to hard water.
  • Temperature: 68 – 82°F (20 – 28°C).
  • Lighting: Low to Moderate lighting.

Care level: Easy.

Propagation: by runners.

Dwarf Sagittaria

PROS CONS
The root system prevents gas pockets. Might be hard to transplant from an emersed form to a submersed form.
Tolerates cold temperatures.  
Easy to care for and propagate.  
Anchors well in the substrate.  
It can thrive in low light.  
Great for nano tanks.  
A great choice for paludarium setups.  

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9. Red tiger lotus

Red tiger lotus (Nymphaea zenkeri)Nymphaea zenkeri, commonly known as the Red Tiger Lotus, is a striking aquatic plant appreciated for its unique appearance and red coloration.

This plant exhibits a phenomenal growth rate. Red Tiger Lotus is capable of taking over the tank if left unattended.

This is a bulb plant, meaning it grows from a bulb that is planted in the substrate. As it grows, it sends leaves to the water’s surface. It can become quite tall (up to 25 inches or 60 cm), making it suitable for the background or midground of an aquarium.

Red tiger lotus features include:

  • Beautiful and charming arrow-shaped or heart-shaped red leaves with prominent raised veins.
  • Focal point in the aquarium due to its appearance.
  • Bulb plant.
  • Requires nutrient-rich substrates.

Basic requirements:

  • Water pH: 6.0 – 8.0
  • Hardness: Soft to hard water.
  • Temperature: 71 – 80°F (22 – 26°C).
  • Lighting: Moderate to High.

Care level: Easy.

Propagation: by daughter plants via bulbs or seeds

Red Tiger lotus

PROS CONS
Beautiful and decorative. Need deep and nutrient-rich substrate.
Easy to care for and maintain. A huge root system makes it hard to relocate.
Hardy. Does not like to be moved.
Fast growth rate. Ugly aerial roots.
The root system prevents gas pockets.  
Great for nano tanks  

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10. Ludwigia Repens

Ludwigia Repens Care Guide – Planting, Growing, and PropagationLudwigia Repens has rightly earned its reputation as a reliable classic, owing to its undemanding nature and the distinction of being the easiest in the genus to care for.

This fast-growing plant usually reaches 10 – 20 inches (25 – 50 cm) in height. Under optimal conditions, be ready to trim the shoots at least twice a month.

Personally, this is also one of my favorite plants as well.  Its adaptability and flexibility make it ideal for aquarium use.

LudwigiaRepens features include:

  • Stem plant.
  • True low-light plant. Under moderate lighting, the leaves will get a nice reddish hue.
  • There are also several varieties of this species with bright red foliage.
  • Can be planted, or floated, but it does best being planted.
  • Can be grown in emersed or submerged environments.
  • Sprouts aerial roots from the internodes of the stems.
  • Requires nutrient-rich substrate.

Basic requirements:

  • WaterpH: 6.0 – 8.0.
  • Hardness: Soft to hard water.
  • Temperature: 68 – 78 °F (20 – 26 °C).
  • Lighting: Low to Moderate.

Care level: Easy.

Propagation: by cutting.

Ludwigia Repens
PROS CONS
A nice looking plant that can change color. Roots overgrowth.
Easy to care. Prefers iron-rich substrates.
Hardy.  
Some species are great for nano tanks.  
Very good at sucking up nitrates and ammonia.  
Easy to propagate.  
The root system prevents gas pockets.  
Good choice for low-tech tanks  

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Some Other Interesting Options:

The above-mentioned plants are quite well-known in the aquarium hobby due to their low demands and resilience.

Nevertheless, if you haven’t found a suitable fast-growing plant for nitrate reduction or if you’re not daunted by working with more demanding plants, you can further expand this list with the following species:

  1. Myriophyllum elatinoides
  2. Limnophila aquatic
  3. Dwarf ambulia (Limnophila sessiliflora)
  4. Creeping Jenny (Lysimachia nummularia)
  5. Monosolenium tenerum
  6. Heteranthera zosterifolia
  7. Rotala indica
  8. Rotala rotundifolia
  9. Crystalwort (Riccia fluitans)
  10. Cabomba 
  11. Pygmy chain sword (Echinodorus tenellus)
  12. Ammannia gracilis 
  13. Madagascar lace

In Conclusion

These plants are not only frequently utilized in aquascaping to decorate aquariums but also serve as hidden aquatic heroes which contribute significantly to the delicate balance of the aquatic ecosystems.

2 crucial factors deserve attention here.

  • Firstly, the importance of light cannot be underestimated.

While there are indeed some plants that can exhibit good growth even in low-tech aquariums, in the majority of cases, at least moderate lighting is one of the most essential factors.

Bright light enables plants to undergo photosynthesis more rapidly, promoting growth and, consequently, nitrate consumption within the aquarium.

  • Secondly, it’s crucial to consider that most fast-growing submerged plants can attain gigantic sizes.

Why is that? The answer is clear—they aim to reach the water’s surface, where they can access an unlimited amount of CO2 and even more light.

Unfortunately, when these plants grow too large, the lower leaves start to receive inadequate light, resulting in a leggy and unattractive appearance.

To prevent this, one must come to terms with the fact that frequent trimming of the plants will be necessary.

On one hand, this preserves their decorative appearance, while on the other hand, it provides them with an additional push for continued growth and, subsequently, nitrate consumption.

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