Last Updated: July 2026
If you’ve discovered a thick, dark green plant growing beneath the surface of your pond, there’s a good chance you’re looking at coontail (Ceratophyllum demersum). It is one of the most widespread submerged aquatic plants in North America and is commonly found in farm ponds, fishing lakes, golf course ponds, stormwater ponds, and natural lakes.
Unlike many aquatic weeds, coontail isn’t always a problem. In moderate amounts it provides excellent habitat for fish and aquatic wildlife. However, when nutrients are abundant and water is clear, coontail can spread rapidly, interfering with fishing, boating, swimming, and even pond aeration systems.
This guide explains how to identify coontail, why it grows, and the best management strategies for keeping it under control.
Quick Identification
Scientific Name: Ceratophyllum demersum
Common Names:
- Coontail
- Hornwort
- Rigid hornwort
Identification Checklist
✓ Entirely submerged
✓ No floating leaves
✓ Usually not rooted in the bottom
✓ Leaves arranged in circular whorls around the stem
✓ Each leaf repeatedly forks into stiff, narrow segments
✓ Plant resembles the tail of a raccoon or bottle brush
✓ Dark green to olive green
✓ Brittle stems that easily break apart
What Does Coontail Look Like?
Coontail has one of the most distinctive appearances of any submerged pond plant.
Instead of broad leaves, each stem is covered with dense whorls of finely divided leaves. Each individual leaf splits into multiple forked branches, giving the plant a feathery appearance. The growing tips become very dense, creating the “coon’s tail” look that gives the plant its common name.
Unlike many submerged plants, coontail typically floats freely in the water column rather than producing a true root system. While portions of the plant may become loosely anchored in soft sediment, it absorbs nutrients directly from the surrounding water.
Where Does Coontail Grow?
Coontail is found throughout most of the United States and southern Canada.
It thrives in:
- Farm ponds
- Recreational lakes
- Golf course ponds
- Retention ponds
- Slow-moving streams
- Reservoir coves
It commonly grows in water ranging from 2 to 15 feet deep where sunlight reaches the bottom.
Why Does Coontail Grow So Well?
Several conditions favor rapid coontail growth:
- High phosphorus concentrations
- Nitrogen availability
- Clear water allowing sunlight to penetrate deeply
- Stable water levels
- Warm summer temperatures
- Little wave action
Healthy ponds with very clear water often experience more submerged plant growth because sunlight reaches greater depths.
Is Coontail Good or Bad?
The answer depends entirely on how much is present.
Benefits
Moderate amounts of coontail provide several ecological benefits:
- Produces oxygen during daylight
- Provides spawning habitat for fish
- Protects young bluegill and baitfish from predators
- Stabilizes bottom sediments
- Competes with algae for nutrients
- Provides habitat for aquatic insects
For many fisheries biologists, 10–20% plant coverage is considered desirable because it supports healthy fish populations without interfering with recreation.
Problems
Excessive growth can create serious issues:
- Difficult fishing
- Tangled boat propellers
- Swimming hazards
- Reduced water circulation
- Interference with fountains and diffused aeration
- Oxygen depletion if large areas suddenly die
- Can dominate shallow ponds
How to Tell Coontail from Similar Plants
Coontail vs. Sago Pondweed
Sago pondweed has long thread-like leaves that do not repeatedly fork.
Coontail leaves branch many times, producing a bottle-brush appearance.
Coontail vs. Milfoil
Milfoil has feather-like leaves with leaflets arranged neatly on each side of a central leaf stem.
Coontail leaves repeatedly divide without that symmetrical feather pattern.
Coontail vs. Fanwort
Fanwort produces delicate fan-shaped leaves and often has floating leaves and white flowers.
Coontail never produces floating leaves and remains completely submerged.
How Does Coontail Spread?
Coontail spreads primarily through fragmentation.
Even small stem fragments can develop into new plants under favorable conditions. This is one reason mechanical harvesting without proper cleanup may unintentionally spread the plant.
The plant also forms dense overwintering buds (turions) that sink to the bottom and begin growing again the following spring.
Best Management Options
Successful control usually combines several approaches rather than relying on a single treatment.
1. Reduce Excess Nutrients
Long-term control starts with reducing phosphorus entering the pond.
Consider:
- Watershed management
- Buffer strips
- Limiting fertilizer runoff
- Phosphorus-binding products when appropriate
- Aeration to improve overall pond health
Reducing nutrients won’t eliminate established coontail overnight, but it can reduce future growth pressure.
2. Mechanical Removal
Hand rakes and aquatic weed cutters work well for:
- Swimming beaches
- Fishing docks
- Boat lanes
Always remove harvested vegetation from the shoreline so nutrients are not recycled back into the pond.
3. Biological Control
In suitable ponds, triploid grass carp may provide long-term suppression of coontail. Effectiveness varies with stocking rate, pond size, alternative vegetation, and state regulations.
Grass carp should be stocked thoughtfully, since overstocking can eliminate beneficial vegetation and increase algae problems.
4. Herbicides
Several aquatic herbicides are labeled for coontail control. Product selection depends on pond size, water chemistry, water use restrictions, and whether whole-pond or spot treatment is planned.
Large infestations should generally be treated in sections over several weeks to reduce the risk of dissolved oxygen depletion from rapid decomposition.
Always follow the product label and local regulations.
Does Aeration Control Coontail?
Aeration alone will not eliminate coontail.
However, a properly designed bottom-diffused aeration system may:
- Improve oxygen levels
- Support beneficial bacteria
- Enhance overall pond health
- Improve circulation
While these improvements benefit the pond ecosystem, they should not be expected to remove established coontail without additional management.
Frequently Asked Questions
Is coontail an algae?
No. Coontail is a true flowering aquatic plant, even though its flowers are tiny and rarely noticed.
Is coontail rooted?
Usually no. Most plants drift freely or are only loosely anchored in soft sediment.
Does coontail survive winter?
Yes. It commonly overwinters as dense buds called turions that begin growing again in spring.
Does coontail help fish?
Yes. Moderate amounts provide valuable cover, spawning habitat, and shelter for young fish.
Should all coontail be removed?
Generally, no. A moderate amount of submerged vegetation is beneficial for pond health and fisheries. Management usually focuses on reducing excessive growth rather than eliminating the plant entirely.
Key Takeaways
Coontail is one of North America’s most common submerged aquatic plants. It is easily recognized by its dark green, forked leaves arranged in dense whorls that resemble a raccoon’s tail. While moderate growth provides important ecological benefits, excessive infestations can interfere with recreation and pond management.
The most effective long-term strategy combines nutrient management, selective physical removal, appropriate biological or chemical controls when needed, and maintaining overall pond health through good watershed management and aeration.
Correct identification is the first—and often the most important—step before choosing any management strategy.