Coontail Plants: How This Plant Can Benefit Your Aquarium

Alison Page

Alison Page


Coontail Plants: How This Plant Can Benefit Your Aquarium

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Live plants have many benefits for the home aquarium and its community. Plants help to oxygenate the water, provide shelter for fish and fry, and create a natural-looking environment that’s aesthetically pleasing. There are many aquatic plants to choose from, including coontail, which is one of the easiest freshwater plants that you can grow in your tank.

In this comprehensive guide, you’ll learn everything you need to know about growing and propagating Coontail in your aquarium or outdoor fish pond.

Coontail Care Guide

What is coontail?

Coontail is a freshwater plant that’s also known by its common name of hornwort, rigid hornwort, coontail, or coon’s tail.

You’ll see coontail in every continent across the globe, with the exception of Antarctica. Regarded as a harmful invasive weed in New Zealand, hornwort is also a popular aquarium and pond plant, growing wild in quiet streams, lakes, and ponds.

There are between 100 and 150 species of coontail, but the most popular that you’ll see in fish tanks is Coontail Ceratophyllum demersum. Ceratophyllum demersum is a hardy aquatic plant that’s perfect for beginners to grow in an aquarium.

You can also grow coontail in your garden pond. However, it can cause problems due to its rapid growth rate and is regarded in some areas as an invasive species. Ceratophyllum demersum has allelopathic capabilities. That means the plant can produce chemicals that deprive other plants of nutrients, creating more space for itself.

The success of the plant and its ease of propagation means that it’s found in most fish stores at a very affordable price. A few bunches of coontail will usually cost around $5 to $10, depending on how many you buy.

When grown in ponds, the seeds of coontail provides food for waterfowl that search through the foliage for these nutritious morsels. Also, the submerged roots of the plants make the ideal habitat for micro and macroinvertebrates, which in turn are eaten by fish, reptiles, amphibians, and water birds. When the plants die, fungi and bacteria cause decomposition, creating “detritus,” which in turn provides nutrition for a host of aquatic invertebrates.

Coontail appearance

Coontail is classified as a submerged aquatic plant. That means the plant grows under the surface of the water. These rootless, free-floating native aquatic plants form dense colonies that rapidly cover the water surface.

One plant has multiple stems, bearing green, forked, serrated leaves that are arranged in stiff whorls of six to 12 needles on the plant’s stem. The overall appearance of the plant resembles a raccoon’s tail, which is most likely how the plant got its common name. In cool water, the leaves are dark green, although, in tropical tanks, the coloration is typically lighter.

Coontail doesn’t have true roots. However, the plant can be anchored in the substrate by some of its leaves, and hair-like roots (rhizoids) will quickly grow to help keep the plant in place. Wild coontail plants can grow up to ten feet in length, and tank-grown plants may reach the surface of the water once established.

The plant bears tiny brown flowers, which is important for reproduction. Coontail is a monoecious plant species, meaning that both female and male flowers are borne by the same specimen. Seeds are also produced in the form of nuts that are 1/5-inch in size, bearing three spines.

Coontail Plants: How This Plant Can Benefit Your Aquarium

Benefits of coontail

Coontail looks great in a home aquarium setup, swaying gently in the current generated by the filtration system, and adding a splash of vibrant color to the aquascape. One of the great things about the plant is that it will grow anchored in the substrate or floating freely on the water’s surface. The waving fronds of the plant also create hiding places and shelter for fish and fry that are trying to escape from the light or from their tankmates.

Like all plants, coontail creates the nutrition that it needs through the process of photosynthesis. Photosynthesis creates oxygen that’s released into the water, which benefits your fish. Also, coontail Ceratophyllum absorbs small amounts of fish waste and nitrogen compounds, helping to clean the water and easing the burden on your filter system. The plant’s allelopathic capabilities retard the growth of blue-green algae, which can rapidly cloak a tank that has too much light or an excess of organic waste.

Finally, as part of the growth process, the plants will occasionally shed a few leaves, which can provide food for fish and invertebrates.


Coontail’s success is also its downside in some situations. In the wild environment, when coontail growth is excessive, it can reduce open water, creating an undesirable “scummy” appearance and causing problems with leisure activities, such as angling, swimming, and boating.

Another downside of these vigorous aquatic plants is that they provide so many hiding places for fish that natural predators are unable to hunt as effectively, leading to an overpopulation of fish and stunted fish growth.

How to care for coontail Ceratophyllum demersum

Although these plants are extremely easy to grow and do well in most home tanks, you’ll find this section of our guide helpful if you’re a beginner to keeping live plants in your aquarium.

Tank conditions

Hornwort grows in a broad range of native habitats, making it ideal for most freshwater tank setups, including cold and tropical. You can grow this plant in any size of the tank, but it does grow rapidly, and you will need to prune it regularly to prevent a total takeover.

A water temperature range of around 590 to 860 will be fine for coontail, with a pH from 6.0 to 7/5 and water hardness of 5 to 15 dGH. A standard filtration system that keeps nitrogen compound levels low is also good, although not essential.

One factor that is of great importance to the coon’s tail plant is plenty of light and clear water that allows the light to penetrate the entire tank. That enables the plant to create the nutrition it needs through photosynthesis. If you have other plants in the aquarium, you may need to add fertilizer each week, as coontail will rapidly devour any available nutrients in the water.

Free-floating or planted?

Hornwort can be allowed to float free on the water surface, or you can anchor it in the substrate. Your decision on that will depend on the look you want to achieve in your tank and on the preferences of your fish. Whichever option you go for, the whorls, long stems, and spiny leaves of the plant provide excellent shelter for small fish and fry.

Be aware that surface-feeders, such as hatchet fish or bettas, may struggle to find food if it becomes too enmeshed in foliage that is covering the surface. However, floating plants provide shade, allowing fish to get away from the light, which can really help to show off their colors.

Bear in mind when planting coontail that it can grow long enough to block a filter inlet. Also, if you intend to anchor the plant in the substrate, fine-grained sand or gravel is best, as it enables the plant’s leaves to be more easily secured.

Pruning and management

As previously mentioned, coon’s tail grows remarkably quickly and needs proactive management to keep it under control.

In the aquarium

When the plant’s stems get too long, use a sharp pair of scissors to nip off the excess growth, working from the top of the stem. Coontail does tend to shed its needles fairly regularly as part of its normal growth process. Use a net to scoop the debris out of the water so that it doesn’t clog your filter intake. Excessive shedding usually happens when the water temperature is too high. Provided that your fish will tolerate it, lowering the temperature may help to solve the problem.

In the pond

If you’re growing coontail in an outdoor pond, the same rules apply. Be sure to prune the plants regularly to prevent them from taking over and clogging the surface of the pond.

There are several options that you can use when it comes to controlling coon’s tail in a large outdoor body of water.

Some herbicides that contain 2,4-D, diquat, endothall, and fluridone have shown good results, but the effects are often expensive and short-term. Caution should be used when using herbicide, as some chemicals can decrease dissolved oxygen levels, which can harm your fish. With any form of herbicide, always follow the manufacturer’s directions carefully. You can find a suitable treatment that may include herbicides through a website search.

For long-term control, grass carp can be effective when stocked at appropriate rates as they will eat coontail. However, you should check with your local wildlife department before introducing grass carp, especially if there is a chance that they could escape into surrounding waters.

Aquarium Plants: Coontail


Coon’s tail is very easy to propagate, reproducing by the process of vegetative fragmentation, which is common to most invasive species. Essentially, one part of the plant separates from the rest, regrowing to form a new one.

The main plant stem sends out multiple side shoots that may become detached, or the process can happen when a whole section or a tiny fragment from the top of the stem breaks free. In the fall, buds appear at the end of the stems. Those buds are shed and lay on the bottom of the pond throughout the winter, growing into new plants when spring arrives.

The easiest way to propagate coon’s tail in your aquarium is to break off a small piece of the plant and allow it to float freely in the water. Within a week or so, the plant will put out thread-like roots and begin to grow.


Coon’s tail is fine for all fish. In particular, livebearers, such as guppies and mollies, will benefit more than most, using the plant as a shelter when mating and producing fry.

Some fish, including angelfish and gouramis, will eat the plant’s leaves, so bear that in mind when selecting new fish species for your community. Snails, shrimp, and loaches will work hard to clear away any shed leaves from the plant.


In this section of our guide to keeping coon’s tail, we answer some of the most commonly asked questions about keeping these vigorous, robust plants.

Q: Is Coontail invasive?

A: Coon’s tail can be highly invasive, rapidly taking over water bodies due to its fast growth rate and tolerance of a wide range of water conditions.

Q: What does Coontail look like?

A: Coontail is light to dark green in color. The plant has long stems with multiple side shoots, ending in whorls that comprise six to 12 needles. The plant will grow on the water’s surface or anchored in the substrate. Coon’s tail bears tiny brown flowers in the summer and buds in the fall.

Q: Is Coontail edible?

A: Coontail is eaten by waterfowl and also by some species of fish, including grass carp. In the aquarium, gouramis and angelfish will sometimes eat the plant’s leaves.

Q: What will kill Coontail?

A: Coontail can be killed by certain herbicides that contain 2,4-D, diquat, endothall, and fluridone.

Final thoughts

Coontail Ceratophyllum demersum is an aquatic plant that grows in ponds and slow streams and can also be grown easily in the home freshwater aquarium.

If you’re looking for the perfect, easy-care plant to add color and aesthetic appeal to your tank, coon’s tail could be a good plant for you to include in your setup. Also, many fish and fry appreciate the shelter that’s provided by the plant’s trailing stems and clusters of needles.

Bear in mind that you will need to prune the plant regularly to prevent it from taking over your aquarium or garden pond.

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