The duckweeds (genus Lemna) and related genera of the duckweed family (Lemnaceae) are the smallest flowering plants known. Individual plants consist of a single, flat oval leaf (technically a modified stem) no more than ¼ of an inch long that floats on the surface of still-moving ponds, lakes, and sloughs.
Nutrient uptake
This cycle needs to be closely regulated if you want to successfully grow other plants in the aquarium as duckweed can quickly deplete the tank of essential nutrients. In order to keep nutrients in check, it's best to manually remove some duckweed every time it begins to grow a little too fast.
Duckweed helps to oxygenate the water and improve water quality. As Duckweed grows, it will spread across the water's surface, creating a dense mat of vegetation that can shade and protect fish from the sun. Duckweed is also effective at absorbing excess nutrients from the water, which can help to prevent algae growth.
In the right amounts, duckweed and algae are beneficial to a pond's ecosystem. Birds and other wildlife consume duckweed. Although filamentous algae has no known direct food value, after it dies the decomposed plant matter forms detritus—a food source for many invertebrates.
If the duckweed covers the surface of the pond, it can block gas exchange with the atmosphere. This can cause problems for fish and other aquatic animals that need oxygen in the water.
It's always best to keep duckweed levels low in fish ponds by regularly removing any overgrowth before it can spread. If levels are allowed to get too high the duckweed will begin to reduce oxygen levels and contribute to an increase in waste, sludge, and harmful substance build-up.
Common Duckweed (Lemna minor) keeps water clean, prevents the overgrowth of algae, and generously feeds fish. Plants measure 1/16 to 1/8 of an inch long. Each plant has one to three light green leaves that are flat and oval in shape. Each leaf then has one hair-like root that hangs down in the water.
What Kind of Fish Will Eat Duckweed? Aquarium fish, wild fish, and even pond fish will eat duckweed. It's a fast-growing tasty treat that fish keepers and farmers can take advantage of. Bettas, mollies, koi, and goldfish seem to find duckweed especially delicious, and Grass carp and tilapia can live off duckweed alone.
There are, in fact, some fish that feed on duckweed, like, for example, the gouramis of the genus Trichogaster. These fish can therefore be quite helpful in containing a duckweed infestation. Of course, they have certain requirements regarding the size of the aquarium and the water quality, which must be considered.
Duckweed is an herb. The whole fresh plant is used to make medicine. People take duckweed for swelling (inflammation) of the upper airways, yellowed skin due to liver problems (jaundice), and arthritis.
The whole fresh plant is used as a food and is sometimes used to make medicine. Duckweed contains large amounts of protein. People use duckweed for infection of the airways, rheumatoid arthritis (RA), gout, and other conditions, but there is no good scientific evidence to support these uses.
Pond maintenance plans including a good bacteria such as NaturalClear Pond Bacteria is the most important supplement as this good bacteria eats up dead duckweed and vegetation, while also reducing the nutrients available for duckweed to grow.
Age‐related declines in survivorship were observed for all three species of duckweed (Figures 1 and 2). In each case, only about 20% of fronds lived beyond age 30 days. However, the shape of each species' survivorship trajectory was distinct with L.
Duckweed growth is optimum at temperatures between 20 and 30 °C, but serious effects will occur at temperatures between 35 and 40 °C. Below 17 °C some duckweeds show a decreasing rate of growth. Duckweed can tolerate a wide range of pH (3.0–10.0), but displays optimum growth in a medium of 5.0–7.0.
Two insect herbivore species have been found to be commonly damaging duckweeds: Tanysphyrus lemnae Paykull (Coleoptera: Brachyceridae)
Use Safe Chemicals. There are safe chemical options that you can use on duckweed to help stop colonies from growing. One of the chemicals on the market is called Sonar™, which contains a chemical called fluridone. Another herbicide that can help with controlling duckweed is diquat dibromide.
Although duckweed fronds are able to produce oxygen, overgrown mats can cause anoxic conditions. This is more likely to occur in deeper, slow-moving ponds that may depend on submerged plants and algae to oxygenate the lower layers of the water column.
Semera or Flumigard (with surfactant) – liquid or granules that are dissolved in water and sprayed (early morning is best) over the plants, fast-acting.
Duckweed is a natural water filter
After a while, the duckweed dies, sinks to the bottom, and releases all the nutrients and contaminants back into the water. To be effective as wastewater treatment, duckweed needs to be removed and disposed of appropriately.
Another thing to consider is the pH level of the water you're using. Duckweed grows best in neutral water, so the pH level should be between 6.0 and 8.0, though 7.0 is best for thriving Duckweed.
From a distance, duckweed can look like a smooth, green blanket covering the water. However, it is really individual duckweed plants that are not connected together. Each duckweed plant has tiny green leaves with small roots that hang below the plant.
Duckweed has one to three small, flat, oval leaves. Although duckweed is not toxic, thick growth can smother water-bodies and kill fish. “When in doubt, stay out,” DEEP said. “The best way to ensure the safety of you and your pets is to avoid contact with water that appears to be experiencing a bloom.”
In its natural environment, it thrives in locations as diverse as marshes and wetlands, rivers, streams, ponds and lakes. If you're wondering whether goldfish eat it, the answer is yes. In fact, Duckweed is great for your fish to snack on. It's nutritious and most goldfish find it to be quite a tasty treat!