Amazon Frogbit Care Guide – Planting, Growing, and Propagation

Amazon frogbit (Limnobium Laevigatum)

Today, we will be talking about a popular floating plant used majorly in the aquarium hobby – Limnobium Laevigatum.

Limnobium Laevigatum is commonly known as Amazon frogbit, it is notable for its vast usage in aquascaping. Amazon frogbit is a perennial flowering plant capable of surviving in almost all kinds of freshwater habitats. This plant has adaptive mechanisms that help it remain buoyant in water bodies and surfaces.

In this article, we will enlighten you on all there is to know about one of our favorite freshwater plants- Amazon frogbit and a detailed guide for planting and maintaining this amazing plant.

Amazon frogbit – check out the price on Amazon

Quick Notes about Amazon Frogbit 

Common Name Amazon Frogbit 
Other Names West Indian Spongeplant, South American Spongeplant, Smooth frogbit
Scientific Name Limnobium Laevigatum
Tank Size (minimum)  20 gallons (~80 liters)
Difficulty Easy
Lighting Medium to high
Optimal pH 6.0 – 7.5
Water hardness    Soft – medium
Temperature 18 – 26 oC (64 to 80 °F )
Substrate Not needed
Growth Rate Moderate to fast growth rate
Placement in Tank Floating
Height Roots can reach 30 cm (12 inches) or more
CO2 Not needed 
Propagation Through plantlets

Origin of Amazon Frogbit

The Amazon frogbit is native to Central and South America. These places were the first areas to witness natural distribution of the plant.

Amazon frogbit with the scientific name: Limnobium Laevigatum first appeared in 1814, this was in an article written by a French biologist Louis Claude Marie Richard. The species took its name from the Greek word ‘limnobios’ which implies ‘dwelling in a lake’.

The Amazon frogbit has further spread to freshwater habitats in Australia, Africa (Zimbabwe and Zambia) and North America (California). It is often considered as an invasive species.

Limnobium Laevigatum is a floating aquatic plant and a member of the family ‘Hyadrocharitaceae’:  this is a flowering plant family comprising 16 known generas with a total of about 135 known species which includes the popular Amazon frogbit. Here is a brief summary of its scientific classification:

Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Order: Alismatales
Family: Hydrocharitaceae
Genus: Limnobium
Species: Limnobium Laevigatum

Amazon frogbit has other names, which include West Indian Spongeplant, South American Spongeplant, Smooth frogbit. The name ‘Spongeplant’ refers to the spongy surface of the underside of its leaves. This structure helps to increase buoyancy so that the plant can easily float and move with the wind & water current.

Habitat of Amazon Frogbit

Amazon frogbit is known to grow in freshwater habitats with soft water and high lighting. The plant can be found in South and Central America, Africa, Asia, Australia and North America where it inhabits slow-moving bodies of freshwater- ponds, bogs, ditches, marshes, and swamps. The Amazon frogbit can spread easily through the dispersal of its seeds, it can adapt and thrive within a wide range of environment and water conditions. 

Description or Amazon Frogbit

Amazon frogbit (Limnobium Laevigatum) with rootsAmazon frogbit has a unique structure and possesses the following features:

  • A near-perfect round or circular structure.
  • Bright green leaves.
  • Smooth and unmarked leaves.
  • Long, fuzzy, branching roots with fine trailing hairs.
  • Flowers that are tiny, white and unisexual.
  • Roots of Amazon frogbit can be up to 20 inches (50 cm) in size.
  • Width of 0.5 to 3 inches.
  • Presence of spongy aerenchyma tissue on the underside of the leaf (for buoyancy).
  • Stolons which bear gametes.
  • Female flowers that have an interior ovary.
  • Rosettes of floating leaves that lie on the water surface.
  • Seeds are 1mm long.l, ellipsoid, and hairy.
  • Long roots that serve as shelter for fry.
  • Production of young plants through rametsa.

Water Parameters and Tank Requirements

In order to ensure that the Amazon frogbit is healthy and kept alive, the following tank requirements and water parameters should be duly maintained.

Tank size:

First, the recommended tank size for this species is a minimum of 10 gallons (~40 liters). The growth rate of the Amazon frogbit is fast and they can easily take over the tank. Nano tanks are not preferred for this species, rather aquarists should opt for tanks with large capacities to accommodate them adequately. 

Water type, Temperature, Hardness, and pH:

Water temperature: Considering the fact that Amazon frogbit dwells in tropics of the world and as such, the same temperature conditions should be replicated in the tank. You should maintain a temperature of 18 – 26 C (64 – 80 F). The plant appreciates normal temperature water, colder water will make the plant grow slowly and small.

Hardness: Amazon frogbit grows better in soft to moderately hard water. For the healthy growth of this species, preferred water hardness is between 0-12°GH.

Water pH: The recommended (optimal) water pH for this species is soft to moderately hard water in the range of 6.0 – 7.5. However, Amazon frogbit is a pretty adaptable plant and can tolerate a wider range of parameters. 

Lighting:

Just like most floating plants used for aquascaping, Amazon frogbit requires moderate – high illumination levels. For this purpose, you can use LED lights, full spectrum T5 or T8 bulbs or fluorescent tubes. Avoid lighting sources with very high intensity as they can burn the leaves. Lighting duration for this species should be between 10 – 12 hours per day.

Amazon Frogbit will not thrive under low lighting conditions. It will stop growing and get sick.

Read more about it in my article “Advanced Guide to Planted Tank Lighting”.

Substrate:

Substrate choices shouldn’t really be a problem. Amazon frogbit is floated on the water column without submersing. The roots hang inside the water column whereas the leaves stay afloat. The Amazon frogbit gets all its nutrients from the tank water through its roots and not from the substrate, therefore any substrate can be used in the tank or chosen according to other factors. Whether you have gravel, sand, aquarium soil, or other nutrient-rich substrate, the Amazon frogbit will do just fine. 

Water Flow:

The plant appreciates slow water bodies, you can replicate this in the tank. Fast water currents might damage the plants especially their long and delicate roots.

Tip: If you have a hang-on-back filter, Amazon frogbit can be pushed around the tank by the surface agitation. The solution to this problem is simple – create a “roped off area” for the plant by using clear air tubing strung across the top of the aquarium. 

Supplements:

Co2:  This plant does not need external Co2 dosing in any amounts whatsoever. It will do just fine with CO2 obtained naturally.

Fertilizer: Amazon frogbit requires lots of nutrients to grow healthily. You will need to supplement the tank water with a   liquid fertilizer when necessary in order to provide the plant with essential nutrients required for optimal growth. You can use Easy Green plant fertilizer for this purpose.

However, if your tank has lots of bioload from fish, snails, etc., external fertilization in this plant species is not mandatory. So, if Amazon frogbit is not showing signs of deficiency then it shouldn’t need fertilizer application.

Important: If you keep shrimp in the tank, I would highly recommend reading my articles:
CO2 in a Planted Tank Guide
CO2 in a Shrimp Tank

How Copper Affects Dwarf Shrimp
Shrimp Safe Plant Fertilizers
The point is that a high level of CO2 and Copper (most fertilizers contain copper) is extremely dangerous to the shrimp. In my article about copper, I also refer to the most popular shrimp-safe plant fertilizers. 

Planting Amazon Frogbit

While planting the Amazon frogbit make sure that you do not submerge the leaves- water is not supposed to touch the top surface of the leaves to prevent them from rotting. It is essential to avoid wetting the leaf surface, care should be taken during water changes and other maintenance activities.

Propagation of Amazon Frogbit

Amazon frogbit is a flowering plant so it reproduces sexually through flower and seed production but this not viable in a home aquarium. In the aquarium, Amazon frogbit propagates vegetatively through stem fragmentation. This process allows mature Amazon frogbit plants to grow smaller plants / plantlets which are set off through ramets / stolons which then detach, grow and develop into a new plant.

Care & Maintenance of Amazon Frogbit

Introduction to the tank: place them on the water column gently. Their roots will submerge in the water column whereas the leaves stays buoyant (this is due to the spongy underside as explained earlier).

After planting the Amazon frogbit, the next step is caring for them in order to ensure that it grows and thrives successfully.

When it feels like the plants are overwhelming the tank, you can get rid of some for disposal. The importance of this is to prevent the tank from becoming stuffed and depriving other inhabitants from getting resources. This plant has a fast growth pattern, which is peculiar to most floating plants. You can also trim the trailing roots if they are getting too long, however, do this gently, the roots of frogbit are fragile.

Extra care should be taken during water changes to avoid submerging the leaves. As mentioned earlier, the leaves rot/ turn brown when the top area comes in contact with moisture (it is meant to stay afloat at all times). You should also keep the roots away from the water filter to avoid getting trapped and damaged.

Another measure is to dose the tank water with liquid fertilizer to boost its nutrient content, which is beneficial to the plants.

Difficulties and Problems of Amazon Frogbit

Rot: This is a major problem that plagues the Amazon frogbit. It occurs as a result of the top surface of the leaves coming in contact with moisture/ water. To avoid this, ensure that the leaves of the Amazon frogbit are kept dry and free from water.

Breakage of the roots: The roots of the Amazon frogbit plant are very long and delicate, and sudden movements and strong water currents can damage them.

Browning of leaves: This condition is a result of the plants not getting sufficient light. To avert this condition you should tone up on the light intensity, you can also remove the affected leaves outrightly. New leaves will form in no distant time.

Shadowing: Amazon frogbit can easily overrun your aquarium in no time, so it will be better to keep in with plants that do not require a lot of light.

Entanglement: The roots can become so long that they can entangle with decorations, other plants, or the tank filters.

You can also read “How to Spot Nutrient Deficiencies in Aquatic Plants”.

Amazon Frogbit & Tankmates

Amazon frogbit is compatible with plants that can thrive in low lighting conditions. Plants like Java moss, American water weed, Anubias, Vallisneria, Sagittaria can be planted alongside the frogbit. As a floating plant, Amazon frogbit blocks a lot of light entering the tank. Furthermore, you should desist from planting other floating plants alongside Amazon frogbit to avoid overcrowding and competition for vital resources.

Amazon frogbit can coexist with almost any kind of freshwater fish. Tetras, clownfish, bettas, gouramis are all compatible with Amazon frogbit. Avoid keeping the plant with aggressive snails that will harm its undersides.

Note: There are many reports that Pond snails really love to eat tender leaves of Amazon frogbit.

Regarding other snails, for example, Ramshorn snailsNerite snailsMalaysian Trumpet snails, Japanese trapdoor snailsMystery snails, etc., you should not worry about it.

This plant is considered to be one of the best plants for the shrimp tank. Read more about it in my article “Top 5 Plants for Your Shrimp Tank” and “Top 5 Pros and Cons of having Plants in Shrimp Aquarium”. It is possible to keep any shrimp species with it. They will love it!

Amazon frogbit is a great choice for any aquarium with crayfish or crabs. It is a well-known fact that these invertebrates are plant destructive (read my introduction to crayfish care). They will eat and uproot everything in the tank. Therefore, the best choice will be to have floater plants like Amazon frogbit.

Benefits of Amazon Frogbit for Aquarium

Removal of excess nutrients: The Amazon frogbit just like most floating plants helps to eliminate excess nutrients and nitrates from the tank water. They grow rapidly, therefore it needs lots of nutrients to keep up with their rapid growth patterns.

Hiding and foraging spots: The long, fuzzy, and trailing roots of the Amazon frogbit provide great hiding spots for shy fish. The roots will also catch all kinds of debris and detritus. So, it is an excellent forage place for fry and shrimp to graze on.

Great for aquascaping: Amazon frogbit floats on the surface of tank water with its long trailing roots immersed deep into the tank water. This plant adds a lot of green to the tank and decorates it with its lush leaves at the top thereby making the tank to be more visually appealing.

Shade / cover: This plant provides shade for fish and fry that thrive in darker environments, as well as low-light aquarium plants that do not need much lighting. Amazon frogbit does a pretty good job in this aspect.

Filtration: Frogbit use their well-adapted roots in providing biological and chemical filtration. They absorb carbon dioxide created by tank inhabitants and other detritus from the tank water thus keeping the water clean and free from bacteria and algae.

Algae control: Frogbit is extremely effective against algae. It outcompetes algae for the nutrients and suppresses its growth.

Buying Amazon Frogbit

Amazon frogbit (Limnobium Laevigatum) cleanWhen buying the plant for cultivation, the number one priority at this stage is getting a healthy plant. Look out for plants with the following features during purchase:

  • Plants with vibrant green leaves (avoid plants with brown/ decaying/ yellow leaves).
  • Plants with normal and healthy long roots.
  • Plants with complete leaves devoid of holes, rips, and cuts.
  • Plants with the absence of curls on the leaves.

Amazing frogbit is a relatively cheap and popular aquarium plant available at most aquarium/ pet stores. You can also source for this plant online from reputable vendors to ensure that you get quality and healthy plants.

Quarantine Frogbit

When you have obtained some healthy plants for cultivation (floating), all you have to do is to quarantine or sterilize them first (using bleach to get rid of parasites and treating them with alum to eliminate snails) before putting them into your tank!

  • They can have parasites, pests like snails, or even predators (dragonfly, damsefly nymphs, etc.).
  • They can be treated with chemicals (pesticide) to remove parasites, snails, etc. However, these chemicals are extremely poisonous to fish, shrimp, and other invertebrates.

To find out more, read my articles:  

How to Remove Snails from a Shrimp Tank.
How to Quarantine and Disinfect Aquarium Plants.
Pesticides in Shrimp Tanks. Plants Quarantine.

In Conclusion

Amazon frogbit is a beautiful and great addition to almost any kind of tank set-up. It is one of the most popular floating freshwater plants for beginners, experts in the hobby also appreciate this plant. Amazon frogbit is inexpensive, easy to maintain, and adds great value to an aquarium.

Related articles:

Top 7 Floating Plants for Beginners

Amazon frogbit – check out the price on Amazon

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