“Duckweed” by Jesi Herterich

Lemna minor, commonly known as duckweed, is a flowering aquatic plant that floats on the tops of slow-moving or stagnant water surfaces. It is typically found in freshwater or wetland ecosystems and grows best in tropical environments. Lemna minor will typically do well in any freshwater tank as it is a fast-growing, low maintenance plant. This is due to its ability to reproduce asexually by budding and cloning in varying conditions. Duckweed is also known to provide freshwater fish with a great source of protein as well as shade for those sensitive to light exposure. Some fish that may enjoy duckweed include; goldfish, koi, bettas, mollys, corydoras, and loaches. 

Duckweed can also be beneficial in ecotoxicity and intake of heavy metals and pollutants as well as water/nutrients. In freshwater ecosystems, duckweed is known to grow and reproduce at rapid rates in areas with high Nitrogen and Phosphorus pollution because of its ability to rapidly uptake nutrients. An abundance of duckweed can block out sunlight, on the one hand, it provides shade in summer for aquatic organisms, but it also will hinder the growth of aquatic plants. An overabundance of duckweed can also deplete oxygen levels in the water and cause an increase in ammonia. This can cause your fish to be stressed, damaging their overall health. Duckweed grows optimally within a temperature range of 6 and 33°C, with about 26°C (79°F) as an optimal temperature. As it grows, it can form a thick surface mat, further impacting the water quality and aesthetics of the tank. 

It is important to monitor the growth of duckweed in an aquarium or water body as excessive growth can have negative impacts on the organisms within the ecosystem. When growing duckweed in a tank, it can quickly become unmanageable with rapid growth and nutrient uptake, intake clogging, unintentional shading, and oxygen depletion for fish. In order to prevent the toxic overgrowth of duckweed, regular maintenance is required. The best way to control duckweed is to manually remove it from the tank every week or so with a net or your hands. It may also be controlled by increasing surface water agitation as it prefers still, slow-moving water for gas exchange.