Caulerpa taxifolia


Also known as:

Killer algae

Family: Caulerpaceae

Origin: Africa, Asia, Australia, North and South America, Oceania

Caulerpa underwater attached to a rock.
This plant can form dense meadows.
Photo credit: Greig Peters, Regional Water Quality Control Board,

Regional Pest Management Plan (RPMP) status

  • Not a legally declared pest

View more about the RPMP statuses

General description

Seaweed < 2.8 m tall. Stolons are creeping and bear flattened, feather-like fronds with many pinnules. Pinnules are opposite, curve upwards and narrow at the tip.

What you need to know

Although caulerpa is not a legally declared pest plant, it may still be invasive in some situations. Consider lower-risk alternatives for your garden, such as native plants.


Nutrient-rich waters, pristine waters, port and mooring facilities, tropical and temperate waters at a depth of < 100 m.


Vegetative spread from stolons and stolon fragments, dispersed by water. Human-mediated dispersal through dumping of aquarium waste and movement of contaminated boats and fishing equipment.

Impact on environment

Outcompetes and smothers seagrasses and other algae, altering habitat and native species diversity. Toxic and possibly allelopathic.


Site Management

Very difficult to control once established. Requires an aquatic pest plant control operator. Contact Auckland Council for control options.

Recommended approaches

Physical control

Method: Pull out.

Plant parts requiring disposal: All parts.

Disposal options: Remove to landfill.


Biocontrol is currently not available for this species.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Close up of caulerpa underwater.
Its fronds are feather-like and flattened with a smooth midrib. The fronds grow from a horizontal runner that is anchored by root-like structures
Photo credit: Rachel Woodfield, Merkel & Associates, Inc.,
Hand holding wet caulerpa.
It can establish in estuaries, harbours and sheltered coastal areas.
Photo credit: Rachel Woodfield, Merkel & Associates, Inc.,