Amazon Frogbit: A Versatile Aquatic Plant for Aquariums and Ponds

Amazon frogbit (Limnobium laevigatum) is a kind of aquatic plants of Hydrocharitaceae family. This is a popular undemanding floating tank plant with round glossy leaves. Provided with proper conditions it can cover all the tank surface with its leaves. In this case you should remove excessive amount of plants. The plant has round, green leaves with a smooth texture and produces small white flowers. Limnobium laevigatum is often used in ponds and aquariums as an ornamental plant due to its attractive appearance. However, it can become invasive if not properly managed, so caution should be exercised when introducing it to new environments.

Plant origin

Scientific name of the kind was fist published in 1814 in the article of a French plant biologist Louis Claude Marie Richard in the 12th issue of Mémoires de la Classe des Sciences Mathématiques et Physiques de L’Institut National de France. The name originated from Greek word λιμνόβιος, limnóbios — ‘dwelling in a lake’.

Natural habitat of the kind is on South-East of the USA (its northern boarder – Illinois, Indiana and West Virginia) as well as Central America and North part of South America. Amazon frogbit was brought to California, where it spread rather wide by pushing out local aquatic plants.

In ecology this kind is expanded in ponds and bogs with lentic or slowly flowing water. The plant stands temperature drop up to ground frosts.

Within its natural habitat, Limnobium laevigatum typically grows in shallow water with calm or slow-flowing conditions. It thrives in areas with abundant sunlight and nutrient-rich waters. The plant often forms dense floating mats or clusters on the water surface, providing shade and shelter for various aquatic organisms.

Amazon frogbit has been introduced to other parts of the world as an ornamental plant for ponds and aquariums. In some areas, it has become an invasive species, negatively impacting native ecosystems. Therefore, it is important to manage its cultivation and spread to prevent any adverse effects on local water bodies.

In the United States, the management of Amazon frogbit primarily revolves around preventing its spread and controlling its population in areas where it has become invasive. If frogbit were to be classified as an invasive species in the future or if it poses a threat to California’s ecosystems, the CDFA may develop management strategies to address its control and eradication.

Scientific NameLimnobium laevigatum
Common namesAmazon frogbit
Smooth frogbit
West Indian spongeplant
South American spongeplant
Native ToUSA
Lighting NeedsHight
Growth rateHight
Temperature Required20-30 °C
pH Level6.0-7.5
Care LevelModerately demanding
Placement in TankFloating plant
Maximum plant sizeleaves are 1,5-3 cm long and up to 0,5 cm thick


Amazon frogbit lamina is round or egg-shaped sometimes; the leaves are 1,5-3 cm long and up to 0,5 cm thick. From above the leaves resemble coins, but if you look closer, you’ll see that their pith is thickened. Bottom of the leaf is porous and absorbing, it looks like a sponge.

The plant leaves contain a large number of aerial cameras. Top of the leaf is bright green and it is silvery from below.

Developed root system forms thick hanging bunches. The roots may grow very long if compared to the remaining part of the plant. They serve not only as a perfect shelter for fish juveniles, but as efficient biological filter as well.

The roots capture the smallest organic particles and other fine organic rubbish; they serve as nutrients for the plant. The plant blossom is thin with elongated petals. Its dioecious or monoecious flowers are either on the same plant or on different plants. The plant has only emersed form.

Amazon frogbit has fibrous roots which perfectly clean tank water from suspended matter. Due to its unpretentiousness the plant is rather widespread among aquarists. In home tanks you can make it grow uniformly during the whole year round.

Difficulties in keeping

Amazon frogbit is quite easy to keep. It grows at almost any conditions and it has high growth rate. Provided with good illumination and sufficient amount of nutrients the plant can cover all tank surface with its leaves.

But it doesn’t mean that you can leave this plant unattended.

Aggressive large fishes can eat up the plant roots and leaves, so such tank mates are harmful for the plant. Besides, to create optimal humidity level it is recommended to cover the tank.

However, frogbit can successfully grow in open tanks as well.

Amazon frogbit has the ability to absorb excess nutrients from the water, helping to reduce algae growth. It also oxygenates the water by releasing oxygen during photosynthesis. By using Amazon frogbit, you can improve water quality and provide a healthier environment for the aquatic inhabitants.

Amazon frogbit Care and keeping in a tank

Amazon frogbit (Limnobium laevigatum) is known for its relatively fast growth rate, especially under favorable conditions. The growth rate can vary depending on factors such as light, nutrients, temperature, and the overall health of the plant. The floating leaves of Amazon frogbit are capable of growing rapidly. They can increase in size by several inches within a week or two, depending on the conditions. The plant will continuously produce new leaves as the older ones age and die off.

Amazon frogbit can serve as a useful indicator plant for monitoring water parameters in an aquarium or pond. Changes in its growth and appearance can provide insights into the overall water quality.

Light requirements

Amazon frogbit like most floating plants requires high illumination level, though it can stand short-time shading. At natural light especially at sunlight the plant looks the most beautiful and reaches it maximal size.

It can show satisfactory growth rate at artificial light as well; LED or luminescence lamps are used for this. It is not recommended to use incandescent electric lamps for this purpose, since they may burn the leaves.

Light day should last at least 8 hours for the plant. In its natural habitat, Amazon frogbit is exposed to varying day lengths based on the season. In aquariums or artificial setups, providing a photoperiod of 8 to 12 hours of light per day is generally suitable for its growth.

Amazon frogbit requires moderate to high light intensity to support photosynthesis and promote robust growth. It typically prefers an intensity of around 50 to 150 PAR (Photosynthetically Active Radiation) or 2,000 to 6,000 lux. However, it can still survive in lower light conditions, although it may exhibit slower growth and elongated stems as it stretches to reach the light source. Full-spectrum aquarium lights or those specifically designed for plant growth, such as those with a color temperature of around 6500K (Kelvin), are commonly used to provide the necessary light spectrum.

If you put light lamps too close to the plant, they may cause burns and even its death. This is because the plant itself grows above the water surface. Amazon frogbit likes proper illumination, but if the lamps produce heat while working, it may damage the plant leaves.

Water temperature

Amazon frogbit is comparatively undemanding in terms of temperature conditions. It can be kept in tropical and moderately warm tanks at temperature from 20 to 30 °C. But it prefers tropical or subtropical climates where the water remains within this temperature range. In colder water the plant grows sufficiently slower and the plant gets smaller.

While it can tolerate slightly cooler or warmer temperatures for short periods, prolonged exposure to temperatures outside this range may negatively affect its growth and overall health. It’s important to maintain the appropriate temperature range when cultivating Amazon frogbit in aquariums or ponds to ensure optimal conditions for its growth.

Water parameters

The ideal pH range for Amazon frogbit is slightly acidic to slightly alkaline, typically around 6.5 to 7.5. Maintaining the pH within this range helps the plant thrive. Changes in pH can impact the health of Amazon frogbit. If the plant’s leaves develop yellowing, stunted growth, or browning edges, it may indicate pH fluctuations. Monitoring and adjusting the pH within this range can help maintain the plant’s health.

In soft water frogbit grows a bit better, than in hard one. Preferable water hardness shouldn’t exceed 10 – 12° KH, violent water reaction isn’t significant. If Amazon frogbit’s leaves start to develop yellowing or browning, it may indicate water hardness issues. The plant may struggle to absorb essential minerals such as calcium and magnesium from the water. Adjusting water hardness or supplementing with appropriate minerals can help resolve this issue.

Nutrient levels

Amazon frogbit is sensitive to nutrient levels in the water. If the plant starts showing excessive growth, with large, lush leaves and rapid reproduction, it may indicate an abundance of nutrients, particularly nitrates and phosphates. This could be a sign of high nutrient levels in the water, possibly due to overfeeding, excessive fish waste, or inadequate nutrient uptake by other aquatic plants.


Hanging straight roots of Amazon frogbit don’t need a substrate, that’s why its characteristics are not significant for the plant. It gets all nutrients and mineral feed from water.


The plant easily and quickly reproduces in a tank. Buds occasionally appear at the end of its short spurs. Gradually small leaves and fibrous roots grow from the buds. When there are more than three leaves on it, the bulbil is ready for separation from its parent plant.

Amazon frogbit (Limnobium laevigatum) can be propagated through various methods, including vegetative propagation and sexual reproduction.

  1. Amazon frogbit can produce small flowers that contain both male and female reproductive organs. Sexual reproduction occurs when the flowers are pollinated, and seeds are formed.
  2. Vegetatively. Amazon frogbit produces small daughter plants attached to the main plant. These daughter plants can be separated from the parent plant once they have developed their own set of roots and leaves. Gently detach the daughter plant from the parent plant and place it in a suitable location in the aquarium or pond.