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Plant guide · Submerged plants

Coontail (Ceratophyllum demersum)

A native, rootless underwater plant with stiff, forked leaves crowded near the tips like a raccoon's tail. It stays green and keeps growing through winter.

Also called: hornwort

A bushy sprig of coontail with dense whorls of stiff dark-green forked leaves on a rocky shore.
Coontail, showing the bushy whorled leaves near the tip. Photo: Ryan Hodnett, CC BY-SA 4.0 (source)

What it looks like

  • Stiff, dark-green leaves that are spiny and forked, crowded near the stem tips (the 'coontail' or 'Christmas tree' look).
  • No true roots: loosely anchored or floating free.
  • Can grow in deep water and often stays green all winter.

Easily confused with

  • Watermilfoils: feather-like leaves rather than spiny, forked ones.
  • Elodea: small flat leaves in whorls of two or three.

Good and bad for your pond

  • Excellent year-round habitat and food: insects live in it, fish feed there, and waterfowl eat it.
  • Grows to nuisance levels where nutrients are high.

Native or invasive?

Native

Native. Native to Pennsylvania and the rest of the United States (Penn State; USDA PLANTS).

USDA PLANTS: CEDE4 (lower 48 states: native)

Do grass carp eat it?

Grass carp eat it

A grass carp food: PFBC lists coontail among their preferred plants, and Penn State says grass carp can control it. Grass carp prefer submerged plants like pondweeds, elodea and coontail; they rarely control algae mats or lilies.

Checked Oct 4, 2026 · Source: Using Grass Carp to Control Aquatic Plants (updated May 19, 2025) This may be outdated

Control options

Prevention first

Penn State Extension's advice for every nuisance plant and algae problem starts with nutrients: overgrowth is a symptom of excess phosphorus and nitrogen from sources such as barnyards, crop fields, septic systems, lawns and golf courses. Cutting fertilizer near the pond, maintaining septic systems, diverting nutrient-rich runoff and keeping a vegetated buffer strip are the long-term fixes; without them, control becomes a yearly chore.

Checked Oct 4, 2026 · Source: Filamentous Algae (updated May 19, 2025) and the companion Penn State plant fact sheets This may be outdated

Remove it by hand or machine

Cutting, raking and harvesting don't work well: small fragments left behind grow into new plants.

Biological options

Grass carp, with a PFBC permit: PFBC grass carp permit needed for each waterbody before buying or stocking; $85 fee, returned if denied.

Checked Oct 4, 2026 · Source: 58 Pa. Code § 71a.10, Triploid grass carp This may be outdated

Chemical options (permit first)

Identify it for certain and measure the pond first. Treat early in the season. Any herbicide or algaecide in a pond needs a joint DEP/PFBC Chapter 91 permit first, at any amount. Only products registered with the U.S. Environmental Protection Agency and with the Pennsylvania Department of Agriculture, and labeled specifically for aquatic use, can be listed on the Chapter 91 permit application. Treat in sections, early in the season: decaying plants can strip oxygen and kill fish.

Checked Oct 4, 2026 · Sources: Water Quality Permitting for Pesticide Applications in Pennsylvania: FAQ (rev. Feb 21, 2025), FAQ #2, #3, #8, #10, #11, #28, #29; Permit Requirement for Use of an Aquatic Herbicide in Ponds (updated Sep 8, 2025); Pond Management (FAQ: controlling submerged vegetation) This may be outdated

Follow the product label; the label is the law. A Chapter 91 permit is required before any herbicide or algaecide goes in a pond (see fact). Consider a licensed applicator.

Sources

Checked Oct 4, 2026