Caulerpa

Caulerpa prolifera

Also known as Feather Caulerpa, Leafy Caulerpa, Caulerpa Algae

SaltwaterMacroalgaeCuttings

Invasive. Caulerpa prolifera is an aggressive invader outside its native range. It was first found on the US West Coast in Newport Bay, California in 2021, where even small fragments establish and displace native seagrass. Never release it or dump tank water into any waterway. Related Caulerpa taxifolia is outright prohibited in several regions.

Caulerpa (Caulerpa prolifera) — Krzysztof Ziarnek, Kenraiz · CC BY-SA 4.0

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Temperature: 73–81°F; 23–27°C
Max height: 5.9 in; 15 cm

Growth rate: Fast
Placement: Background
Type: Macroalgae
pH: 8.0–8.4
Spread: 15.7 in (40 cm)
Nutrient uptake: Water column
Growth region: Submersed
Difficulty: Easy
Family: Caulerpaceae
Origin: Warm coastal waters worldwide, including the Mediterranean, Caribbean, and tropical Atlantic

Overview

Caulerpa is a fast-growing green macroalga that reef keepers use mainly as a refugium workhorse for nutrient export. It is rated easy.

Did you know

A frond sliced off Caulerpa seals its wound and regrows. That is why a stray fragment can seed a whole invasion in the wild.

Caring for Caulerpa

Caulerpa roots into sand, so give it a display or refugium with a substrate rather than a bare glass sump. A cut piece replanted in the sand grows into a new patch.

It wants medium light and moderate flow, and it needs no added CO2. It feeds almost entirely from the water, stripping out nitrate and phosphate that would otherwise feed nuisance algae. Keep it at 73 to 81°F (23 to 27°C) with a pH of 8 to 8.4.

It grows fast and will not stop growing as long as it is fed. Trim and remove the excess regularly, because that harvest is what actually exports the captured nutrients.

The real risk is the plant going sexual. A stressed patch or a sharp nutrient crash can make it release its contents and crash overnight, clouding the water and dumping nutrients back in. Many keepers run the refugium light 24 hours a day and never let nitrate and phosphate hit zero.

Good to know

Caulerpa prolifera is coenocytic. The entire plant is one giant cell with many nuclei and no internal cross-walls, so cytoplasm streams freely through the stolon, upright fronds and rhizoids. It anchors with those rhizoids rather than true roots. Like other Caulerpa it can undergo holocarpic sexual reproduction, turning nearly its whole body into gametes at once and then dying back.

In the wild

Caulerpa is a green macroalga of shallow tropical and subtropical seas. It roots into sand, mud flats and seagrass beds with a creeping horizontal stolon that sends up flat, blade-like fronds. It grows across the Mediterranean, Caribbean and warm Atlantic, where nutrient-rich, brightly lit shallows let it form dense, low meadows.