Two plant names familiar to those active in the fishkeeping industry are Salvinia (minima) and duckweed. The floating aquatic plants make for great aquarium and pond plants in some situations, both adding some attractive shelter for your fishy friends, nutrients, and other benefits.
And though the plants look somewhat similar if you’re not overly familiar with them, they are very different. So, let’s take a look and see which plant is known for what – and which one might be best for your setting.
Comparing Salvinia Minima vs. Duckweed
|Classification||Salvinia minima, or water spangles; with 12 known species||Lemnoideae or Lemna; with 14 known species|
|Description||Vivid green with round or elliptical leaves that grow in clusters of three, with fine white hairs growing on the leaves.||Tiny round thalli (leaf-looking components) that reach up to 1/4 inch in length.|
|Uses||Aquatic plants for cover and ornamentation in an aquarium or pond, as well as leaching heavy metals from water.||Useful for feeding livestock, fish, and other creatures, and has medicinal purposes for treating gout, inflammation of the bronchi, liver disease, and rheumatoid arthritis.|
|Origin and growing preferences||Native to the Americas and Africa, does best in brackish and slightly salty water that’s nutrient-rich.||Originated in North America and prefers warmer climates or goes dormant and sinks down in cooler climates in winter.|
|Special features and interesting facts||Used for removing heavy metals from water.||Prolific plant with sometimes hundreds of thousands of “leaves” in each square meter of water.|
Key Differences Between Salvinia Minima and Duckweed
While the two aquatic plants have similar uses (specifically aquarium plant use) and look somewhat alike, they are two very different plants with overall varying purposes that make a huge impact on how they’re seen and used in both the fishkeeping world and the world at large.
Salvinia Minima vs. Duckweed: Classification
Commonly referred to as water spangles, Salvinia minima belongs to the Salviniaceae family, a rootless aquatic fern that floats on or just below the surface. There are 12 known species primarily found in the tropical regions of Africa and the Americas. The plant is also known as common salvinia or water fern.
Duckweed, though it looks similar, belongs to an entirely different family, the Araceae. Lemnoideae, or Lemna, the scientific name(s) for this popular aquarium plant, is native to North America and are morphologically divergent in their family. There are 14 known species of the plant recognized.
Salvinia Minima vs. Duckweed: Description
Water spangles are a vivid green plant in most cases, with round or elliptical leaves that grow between 0.15 to 0.79 inches lengthwise and have notched and round or heart-shaped apexes at the base. The plant grows sets of leaves in three, and the rhizomes of the plant float on or just below the surface. Fine little hairs grow on the surface of the leaves, repelling water, which is part of what keeps them afloat.
Duckweed technically do not have leaves, but rather thalli, which appear to be leaves. Most of these thalli never exceed 1/4 of an inch in length. These thalli also float on or just below the surface. These are actually the smallest flowering plant that humans have identified thus far, though their flowers are almost never seen. The flowers consist of two microscopic staminate flowers and one pistillate flower, all situated into a pouch-like sac, which is why you’re likely never see them, even if your plants at home bloom.
Salvinia Minima vs. Duckweed: Uses
Water spangles and duckweed are both fast growing plants that have been explored for many purposes. The most solid purchase either have made in the world have been for aquarium care. Salvinia minima is particularly useful for helping to clean up an aquarium, while duckweed is great as a feeder plant. They both provide shelter and shade for fish and invertebrate life below, as well.
The big difference in use for the plants, though, is that duckweed is useful for medicinal purposes and feeding livestock. The plant is rich in protein, making it a great food source, but the plant has also been used to treat gout, rheumatoid arthritis, liver disease, bronchitis, and other conditions related to swelling of the bronchi. (However, this is only for information purposes, we do not recommend using the plant for medical uses. Always seek the opinion of a medical professional.)
Salvinia Minima vs. Duckweed: Origin and Growing Preferences
Salvinia minima grows natively in the Americas, ranging from Mexico all the way down to Argentina, an some parts of Africa, though it was first reports in New York in 1814 and later discovered in southern states as well. It is believed the plant was transferred to North America and does not grow natively there. Duckweed, on the other hand, is native only to North America. Both are floating aquatic plants that may be found in a huge number of waterways and bodies of water throughout their regions, though, and are typically considered invasive because of their intense capability of overgrowing and dominating an area.
Both plants are free-floating, rootless plants that typically grow on the surface of still or nearly-still water sources like ponds, low-flow creeks, canals, and lakes. Salvinia minima does best in water with a salinity of 4 to 7 parts per thousand (ppt) but also thrives in brackish water like swamps, wetlands, and marshes. They’re often found in private ponds and lakes as well. The plants need nutrient-rich water to thrive.
Duckweed prefers water with pH levels between 6.5 and 8, tolerates temperatures as cold as 42 degrees Fahrenheit and becomes dormant in winter in colder climates.
Salvinia Minima vs. Duckweed: Special Features and Funs Facts
Water spangles and duckweed are both invasive species, so their planting and care needs to be precise. Also, in many locations, there are regulations restricting their use outdoors. But there are other unique things about the two plants that make them quite different.
First, duckweed may have hundreds of thousands of thalli per square meter. A thallus is one of the “leaves” which actually is neither leaf nor stem. The plant lacks a true root and vascular system. This is part of why they grow so easily, float so well, and explode their population with no real effort on your part. And because of this huge boom in availability from a limited planting, duckweed is often harvested to feed livestock. The plant is high in protein without being an animal product, so it’s safe to feed to cows and similar creatures that eat a plant-based diet.
On the other hand, water spangles are often favored in the aquarium industry not for food but because they remove heavy metals from water. This makes aquariums much safer for fish and other creatures who often find copper and other metals toxic.
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The photo featured at the top of this post is © Qinan Akmalin/Shutterstock.com
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- , Available here: http://www.iucngisd.org/gisd/species.php?sc=570
- WebMD, Available here: https://www.webmd.com/vitamins/ai/ingredientmono-426/duckweed
- , Available here: https://www.nps.gov/miss/learn/nature/duckweed.htm