10 Best Oxygenating Pond Plants for a Healthy & Clean Pond
by Tory Jon | Last Updated: November 01, 2021
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Oxygenating pond plants are vital for the health of your pond.
They filter undesired pollutants, consume nutrients that would otherwise feed algae growth, and provide shade to protect pond fish and other wildlife.
Oh, and they help produce oxygen in your pond!
But, with so many types of pond plants available, how do you know which ones will add oxygen and help clean up your pond?
Let's take a look at 10 of the best oxygenating plants for a small pond and learn more about these natural wonders.
10 Best Oxygenating Pond Plants
1) Anacharis (Elodea densa)
Elodea, commonly known in North America as Anacharis, is a fast-growing oxygenating plant popular in aquariums and ponds alike.
Pond fish tend to love this pondweed both as a food source in its own right and as a hiding place for small worms and other morsels. The same hardiness and aggressive growth rate that make it such a mainstay in ponds have also led some states to ban this variety of Anacharis as an invasive species.
- How to plant: Elodea densa fends well for itself. Bunches of 4-6 stems can be weighted and dropped into the water every three feet or so. Once they have reached the bottom, they will quickly anchor themselves and begin to grow upward. For more information, check out our guide on how to plant anacharis in a pond.
- Light Requirements: Full sun to partial shade
- Water Depth: Minimum 10" of clear water
2) Anacharis (Egeria najas)
This variety of Anacharis features narrower leaves and is less hardy overall. This offsets somewhat the tendency of Elodea densa to outgrow its environment. On the other hand, Egeria najas can thrive both as a rooted and floating plant, conveying the benefits of each depending on how it is planted.
- How to plant: Because Egeria najas do not form a significant root structure, they can be planted traditionally or placed on the pond’s surface to grow as a floating plant. When used as an oxygenating plant, it is grouped in bunches of 4 to 8 stems, and the bunches are weighted as with Elodea densa.
- Light Requirements: Full sun to partial shade
- Height: 6" to 10'
- Water Depth: Minimum 10" of clear water
3) Red Ludwigia
Red Ludwigia is a fast-growing, highly adaptable pond plant that thrives in shallower waters. When conditions are right, it can reach the pond’s surface, qualifying it as an emergent plant; it has even been known to float unanchored to the ground. Its beautiful leaves, which grow more deeply red with more sunlight, make it an attractive complement to other pond plants and a favorite hiding place for young fish.
- How to plant: Red Ludwigia can be weighted and dropped like other exceptionally hardy pond plants, or potted and its container submerged. For more information, check out our red ludwigia care and grow guide.
- Light Requirements: Full sun to partial shade
- Water Depth: 2” minimum
4) Hornwort (Ceratophyllum demersum)
Also known as coontail, hornwort is a hardy oxygenator whose frilly leaves provide excellent cover for eggs, small fish, and tiny invertebrates. Hornwort doesn’t grow as rampantly as other pond plants, nor does it like to double as a floating or emergent plant. It's purely an under water pond plant. But that can be a point in its favor: its more deliberate growth means that hornwort is less likely than plants like Anacharis to displace other pond plants.
- How to plant: Hornwort is usually sold as bundles of live plants, which can be weighted like other submerged plants and dropped every two feet or so from the water’s surface and left to sink and develop roots in the pond’s floor. Check out our Hornwort Care and Growing Guide for more information.
- Light Requirements: Full Sun to partial shade
- Water Depth: Up to six feet
5) Mermaid Plant
Mermaid plant, or Mermaid Weed, is an excellent choice for shallow waters near your pond’s edges. While it can thrive as a fully submerged plant, its delicate fern-like leaves especially enjoy emerging above the water’s surface. When allowed to do so, Mermaid Weed offers an ideal location for young fish to hide: its leaves provide cover from airborne and water-dwelling predators, and its preference for shallow waters means that the ambient temperature tends to stay high. Mermaid Weed is a relatively slow-growing aquatic plant.
- How to plant: Bunches of Mermaid Weed can be weighted and sunk every two feet or so or placed in planters or baskets.
- Light Requirements: Full Sun to partial shade
- Water Depth: Up to eight inches
6) Cabomba
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Cabomba, or fanwort, is a vivaciously flowering pond plant, unlike the first five oxygenating plants on this list. During springtime, its feathery leaves provide an ideal landing place for eggs and a perfect safe zone for young fish. In the summer, it reaches for the water’s surface and blooms with tiny white flowers. Cabomba prefers moderate temperatures and should not be planted in areas that remain consistently warm.
- How to plant: Cabomba can be weighted and sunk every two feet or so or planted in gravel-filled pots. Check out our guide on how to plant cabomba in a pond for planting and care tips.
- Light Requirements: Full sun to partial shade
- Water Depth: 6” to 3’
7) Vallisneria
Vallisneria, also known as eelgrass or tapegrass, is a popular aquarium plant that thrives in outdoor ponds. Unlike many pond and water garden plants, Vallisneria aggressively develops runners beneath the soil and propagates across wide areas if left uncontained. When planted in large pots, it grows lush lengths of flat leaves up to six feet long, providing excellent oxygen generation and ample cover for young fish.
- How to plant: Because it can quickly take over large stretches of your pond, Vallisneria should always be potted, ideally in light, sandy soil. Check out our guide on how to plant Vallisneria in a pond complete with care and growing tips for more information.
- Light Requirements: Full sun to partial shade
- Water Depth: 10” to 6’
8) Moneywort (Creeping Jenny)
Moneywort, also known as Creeping Charlie or Creeping Jenny, can be a scourge of lawns. But in ponds, it can quickly grow around the water’s edge to provide an attractive transition between land and water and an important habitat for frogs, insects, and young fish. It is extremely hardy, grows rapidly, and stays low, so Moneywort should always be planted near the water’s edge, in boggy conditions. Even rocky barriers between a pond’s edge and grassy areas may not stop Moneywort’s advance; weeding may be necessary if it is intended only to grow around your pond or water garden.
- How to plant: Moneywort is a bog plant that is best planted in shallow water near the edge of your pond and around rocks or a waterfall. Get step-by-step planting instructions and care tips in our how to plant creeping jenny guide.
- Light Requirements: Full sun to partial shade
- Water Depth: 1" to 4”, or in boggy soil
9) Lemon Bacopa
Lemon Bacopa is another fast-growing plant ideal for the boundary between your pond’s surface and the surrounding land. It can thrive as a completely submerged plant but does incredibly well when planted close enough to the pond’s edge to allow it to reach the surface and bloom into bright blue flowers. Its small, succulent leaves give off a lemony scent, especially when crushed; some pond owners allow Lemon Bacopa to grow well inland, where it releases even more fragrance when crushed underfoot.
- How to plant: Lemon Bacopa is a hardy bog plant best suited near the edge of ponds but can flourish fully submerged or even as a floating plant. Check out our guide on how to plant Lemon Bacopa in a pond for more planting and care tips.
- Light Requirements: Full sun to partial shade
- Water Depth: Up to 6” if submerged; otherwise in moist, boggy areas or as a floating plant.
10) Rotala
Rotala originates in Southeast Asia, where it is commonly found on the edges of rice paddies. It is another versatile pond plant, happy either fully submerged or emergent when planted near the pond’s edge. Rotala plants are excellent oxygenator plants for ponds and are especially adept at absorbing excess nutrients before they feed unwanted algae growth. While most species of Rotala feature thin, generously spaced leaves that provide marginal habitat for invertebrates and young fish, it grows densely and quickly, making larger patches of Rotala especially inviting safe zones for vulnerable aquatic life.
- How to plant: Individual specimens can be planted in shallow water; to keep Rotala from propagating, it may be placed in containers with its roots in fresh water. Check out our guide on how to plant Rotala in a pond for more planting and care tips.
- Light Requirements: Full sun to partial shade
- Water Depth: 2" to 24" of clear water
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Types of Pond Plants
All types of water plants offer immediately recognizable benefits for your pond or water garden.
While providing an attractive border along the water’s edge, they control the pond’s margins by inhibiting soil erosion. Lilies and other plants that reach beyond the pond’s surface can offer a refreshing and ever-changing visual element and provide valuable cover to fish from birds and other predators.
But the most vital advantages of pond plants are conveyed underwater. Plants, especially submerged plants, generate oxygen and help regulate the growth of algae by casting shade and absorbing excess nutrients. They also serve as hiding places for eggs and fry.
Some oxygenating plants live entirely underwater, some float, and others split the difference. A mix of these three broad categories tends to be best for most ponds.
Submerged Pond Plants
Though casual observers rarely see them, submerged plants or oxygenating plants are crucial to the health of any pond garden pond. These aquatic plants live entirely underwater, generating oxygen, absorbing potential contaminants such as nitrates, and helping control pond algae by consuming nutrients.
Submerged plants also offer several passive benefits. Their shade inhibits the growth of algae, which in turn contributes to healthy oxygen levels. Many oxygenating plants also provide excellent hiding places for eggs and baby fish, making them a staple in koi ponds. Unlike a lot of plants, most submerged plants are hardy enough to survive winter dormancy. Most can be planted in weighted pots.
Emergent Pond Plants
Emergent plants grow from the pond’s floor to above the water’s surface. Because they have so far to travel before reaching maturity, many emergent plants prefer to live near the water’s edge. Water lilies are a notable exception, but the lotus, cattails, and other bog plants prefer warm water and plenty of sunlight.
Emergent plants offer the same benefits of shade and cover as submerged plants and tend to be crucial food sources for aquatic life. While emergent oxygenating plants can thrive in most hardiness zones, most are not equipped to survive harsh winters. They can be planted in anything from lightly submerged pots to highly saturated soil.
Floating Pond Plants
Floating plants absorb nutrients directly from the water through delicate root systems that needn’t be anchored to the soil. They provide a vital zone of interaction between water and air, inviting everything from insects to beneficial pond bacteria to grow on them. Their leaves and petals provide the pond’s first layer of shade, and their roots convey the same cover and dietary benefits as submerged and emergent plants.
Some floating plants consume high levels of oxygen, so they should always be balanced with significant additions of oxygenating plants. Some particularly aggressive floating plants, such as water hyacinth, are so disruptive to natural waterways that they are banned in some locations.
Floating pond plants are sensitive to cold, and most varieties do not tolerate temperatures below 65 degrees Fahrenheit. Most are purchased as whole plants and are simply placed on the pond’s surface.
Benefits of Oxygenating Pond Plants
Plants that grow entirely underwater are vital to the health of your pond or water garden. They act as pond filters for nitrates and other pollutants, absorb nutrients that would otherwise drive the growth of undesirable vegetation, and provide shade that inhibits the overgrowth of algae. But their primary benefit is their ability to generate healthy levels of oxygen in the water.
Because water does not hold oxygen nearly as well as air, your pond must include a continuous, reliable source of oxygen. Most fish species begin to suffer when levels of dissolved oxygen (DO) drop below 6%. At that point, they may recover less readily from injury, be less resilient to changes in weather and food availability, and spawn less successfully. DO levels below 3.5% may be lethal to fish.
While mechanical pond aerators alone can maintain sufficient DO levels in some ponds, submerged plants are an effective complement, and are more attractive, reliable, and economical, to boot. They also provide several side benefits. Most importantly, they consume nutrients and sunlight that would otherwise encourage unhealthy levels of phytoplankton (microscopic photosynthetic organisms that live in water) and other algae. Phytoplankton is a vital part of any pond's ecosystem, but it can multiply quickly. When algae grow beyond useful levels, it consumes oxygen and nutrients needed by the rest of the pond inhabitants and can look terrible, too.
Oxygenating plants for fish ponds also have an added benefit; they provide vital hiding places for fish and other animals like pond snails. Both koi and goldfish lay clutches of eggs designed to stick to stable surfaces within your pond; when they anchor themselves to a plant that offers dense cover from external threats, eggs have a much better chance of developing into healthy mature fish.
Can You Have Too Many Oxygenating Pond Plants In A Pond?
Too many oxygenating pond plants can cause stress on your pond at night due to the reversal of gases, leading to a drop in dissolved oxygen levels. As a rule of thumb, up to one-third of your pond's surface should be covered with oxygenating plants.
In other words, during sunlit hours, aquatic plants help generate the oxygen that fish and other animals consume. But after dark, these same plants consume oxygen in the pond. Because water retains oxygen far less readily than air, this daytime-nighttime cycle can lead to dramatic drops in DO levels as the night wears on. A pond with too many oxygenating plants may never see DO drop to levels fatal to fish, but its DO cycle might include periods of undue stress.
So, again, covering one-third of your pond with oxygenating plants and using an aerator to establish a consistent baseline of oxygen production is recommended. This keeps the DO cycle steadily within a healthy range for fish while conveying all the side benefits - algae suppression, habitat for young fish, and so on - that make submerged plants so useful.
How Do You Grow Oxygenating Plants in a Pond?
Most oxygenating pond plants should be weighted and dropped into the pond or potted in a container and submerged. With that said, the potting and care instructions will vary by species of plant.
Check out our guide on how to plant aquatic plants in a pond for step-by-step planting and care instructions for a variety of pond plants.
