Is Duckweed Bad for Aquariums? Yes and No!

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Written By Fun Fish Tanks

I Love my Fishes 

We all know that live plants are very beneficial in an aquarium. It should be included in the setup of every aquarium. By having live plants in your aquarium you will have help with a lot of things.

Live plants help with oxygenation, cleaning of the aquarium, absorbing toxic chemicals like ammonia, and so on. There are also a lot of choices when it comes to living plants in an aquarium

Duckweed is one of the most popular aquarium plants. They bring in all the benefits that an aquarium plant must possess in an aquarium. But for some reason, there is a widespread belief of them being deemed unfit for an aquarium. Well in this article we will get into details about duckweed and see if duckweed is bad for your aquarium. 

What is Duckweed? 

What is Duckweed? 

Duckweed is a floating plant that, while many species have minuscule blooms, is a flowering plant that belongs to the Araceae family; several species within this family are the tiniest blooming plants now known to science.

These floating blooming plants are from five distinct genera, all of which are members of the Lemnaceae family: Lemna, Landoltia, Woffiella, Wolffia, and Spirodela. 

The Lemna genus comprises the majority of the hobby’s aquarium duckweed species. A regulated method of reducing excess nutrients in particular rivers has been utilized duckweed because of its fast uptake of nutrients; this duckweed is then frequently harvested and used as fertilizer and livestock feed.

Where do duckweeds come from? 

Where do duckweeds come from? 

On practically every continent, slow-moving lakes, rivers, and pond systems are home to duckweed. It often grows in thick mats on the water’s surface, and if you don’t know what you’re looking at, it can initially appear to be algae.

Except for Antarctica, duckweed may be found all over the world: in Southeast Asia, North America, Africa, and Australia. Lemna-related species are common in North America and Southeast Asia.

Wolffia members are well-liked in Australia and Africa, whereas Wolfiella is common in America and Africa.

Is Duckweed Bad for Aquariums? 

Duckweed is not bad for aquariums. The reason that you might think of it as trouble is when they populate your aquarium so much.

The speed by which the Duckweed’s number increases is something to look out for. Their population increases at an alarming rate, so much so, that instead of benefitting your aquarium it can cause trouble for it. 

Taking in too much nutrient 

If it increases in number too much then they might take in too many nutrients. If you don’t keep an eye on the growth of your duckweed population, it might eventually starve the fish tank of all nutrients, leading to a die-off that could lead to an increase in ammonia levels and the start of a new water cycle.

It can reproduce more quickly as it consumes more nutrients, which ultimately results in more duckweed plants using even more resources. If you wish to successfully grow other plants in the aquarium, you must carefully control this cycle since duckweed may quickly deplete the tank of vital nutrients. 

So you will have to remove the excess duckweed with your own hands. If you do not do it then in no time it will take over your aquarium. 

Blocking equipment 

It might be difficult for aquarists to keep duckweed off of their aquarium equipment because of how quickly it spreads. Duckweed may be challenging to remove since it likes to become entangled in filter intakes and powerheads. 

In general, it may be quite challenging to get rid of a duckweed colony from the aquarium at any one moment since, no matter how many times you try to get rid of it, it always seems to come back. 


As Duckweed cover the surface of the water of your aquarium, they are excellent if you have species of fish that prefer low levels of light. Although this is not great all the time.

Sometimes because of the covering of Duckweed, your tank may be blocked from light too much. Additionally, as they spread rapidly, they can grow over areas in which light is required. 

Also, it might be troublesome for other plants in the aquarium. Light is necessary for photosynthesis and the growth of plants. Duckweed has the best circumstances to outcompete most other species since it is located nearer the light source than most other water plants.

This implies that it is simple to prevent other species with high light requirements from obtaining the illumination they require to survive. 

Benefits of Duckweed in an aquarium 

As far as everything goes, Duckweeds are good for aquariums. Lets go over the benefits that it has for your aquariums. 

Protection for your fish 

As Duckweeds cover the surface in the tank and they do it pretty effectively, some fish species can use it as a cover for protection. Also, if you have the species of fish that tend to jump out of the aquarium then they provide a good cover. As they cover the surface of the water, the fishes might change their mind to jump out of the water

The dense clump of duckweed may act as a shade for your aquarium, slowing the pace at which water evaporates from it and preserving a cool, tanning habitat.

Algae control 

As Duckweed require nutrients to grow, they absorb a lot of nutrients for proper growth. They absorb nutrients like nitrates and phosphates, and these are the nutrients that promote algae growth. So with Duckweed in your aquarium, algae will remain under control. This aquatic floating plant helps a lot with algae control and an aquarist can opt for it if they want to control algae control.

Absorbs the toxic substances

As Duckweed absorbs nutrients, then it absorbs nitrates and ammonia as well. Ammonia and Nitrates are unwanted in your as they are harmful to your fish. So these chemicals will be absorbed by Duckweed, so they contribute to the healthy life of the fishes as well. 

Food Source for Fishes 

Duckweed is a great source of food for herbivorous fishes. The nutritional composition of duckweed makes it a perfect food source for fish and other aquatic creatures. This plant has 5% fat, 25% fiber, and over 40% protein.

It is a fantastic source of protein for your fish because its protein level is comparable to that of animal flesh. It also includes calcium, zinc, phosphorus, sodium, potassium, and sodium. Duckweed is a reliable source of extra food and a tasty snack for fish. 

How fast do Duckweeds grow? 

One of the fastest-growing plants in the world is duckweed. It has been shown that certain species may reproduce in as little as two days.

Although their blossoms are virtually undetectable, they are still blooming plants, thus they are still capable of sexual reproduction. This is why they grow so quickly. They have a very successful technique of replication that can either be by asexual budding or through sexual reproduction. Therefore, they can outgrow rival plants that compete for resources. 

In an aquarium, when the conditions and the water parameters are in optimal condition, they grow rapidly. 


Duckweeds are one of the most popular and the easiest aquatic plants to grow in an aquarium. They are beneficial for your aquarium as well. They absorb nutrients, therefore controlling algae, protecting your fish, and many more.

But this aquatic plant’s growth speed is troubling. This is the only reason that some aquarists believe that these are not ideal for aquariums. They can take over the surface of your aquarium rapidly and might cause problems in the aquarium.

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