Many different species of animals are known to eat common duckweed (lemna minor). Birds, fish, mammals, reptiles, insects, amphibians, and crustaceans eat it. Even humans eat duckweed in some parts of the world! This is because of its high levels of protein and other nutrients, as well as its fast growth rate and easy harvest methods. Duckweed is a major food source for many fish farms for these same reasons. Alternatively, certain fish can also be introduced to ponds and smaller lakes to control the growth rate of duckweed.
Birds and Ducks
As its name suggests, ducks do indeed eat duckweed, and it is a major part of their diet when it is found in their habitat. Ducks do not generally eat enough duck weed to have a noticeable impact on its overall growth rate or surface coverage. In addition to ducks, many other birds will occasionally snack on lemna minor.
Many kinds of fish eat duckweed, including many species of carp, koi, and goldfish. Many commercially farmed fish are fed duckweed as a large part of their diet as duckweed is very high in nutrients and easy to grow and harvest. Tilapia are very commonly grown in this way in fish farms around the world.
Most fish that are not pure predators will eat duckweed if it is found in their environment, even if the lemna minor plant is not found in their native habitats. Most tropical fishes with no prior experience with duckweed will have no reservations about eating it if they are put into an aquarium where it is growing. For this reason duck weed is a favorite aquatic plant for aquarium and aquaculture hobbyists because it can be easily and cheaply grown as a “background” sustainable food source. Once duck-weed is introduced to an aquarium it will usually grow quickly without any help, and will generally provide more than enough food for the fish below, as well as providing shade and helping to naturally clean and purify the water.
Many types of mammals also eat duckweed when it is found in their environment. Duckweed is a favorite food for beaver, muskrat, and other small to mid sized mammals that live in and around water where it grows.
Duckweed is also used in livestock feed for pigs, cows and other domestic farm animals. It is a low cost, high nutrient animal feed that can be grown throughout the year. Due to its rapid growth rate it is becoming more and more common as a livestock feed option around the world.
Amphibians and Reptiles
Many amphibians such as frogs and toads eat lemna minor plants. Snapping Turtles and Painted turtles also like to snack on it, though it is usually not as large a part of their diet as it is with some fishes and birds.
As you can see there are many different animals that commonly eat the duck weed or lemna minor plant. It is a large and very important piece of the ecosystem anywhere it is naturally found. If you are having trouble controlling duckweed in your pond, consider introducing some fish or other duckweed-eating animals before trying harsher, more expensive chemical based pond weed treatments. Colorful fish that eat duckweed can be a great addition to your small pond.