Maiden's Hair Algae

Chlorodesmis fastigiata

Also known as Maidens Hair, Turtle Weed, Green Hair Plant

SaltwaterMacroalgaeCuttings

Maiden's Hair Algae (Chlorodesmis fastigiata) — Dr. Robert Ricker, NOAA/NOS/ORR · Public domain

Care at a glance

Light: High light
CO2: No CO₂ needed
Temperature: 73–81°F; 23–27°C
Max height: 3.1 in; 8 cm

Growth rate: Medium
Placement: Epiphyte
Type: Macroalgae
pH: 8.0–8.4
Spread: 5.9 in (15 cm)
Nutrient uptake: Water column
Growth region: Submersed
Difficulty: Medium
Family: Udoteaceae
Origin: Tropical Indo-Pacific reefs, including Palau, Guam, and the Great Barrier Reef

Overview

Maiden's Hair Algae is an ornamental green turf macroalga for reef tanks. It is rated medium in difficulty.

Did you know

Maiden's Hair Algae hosts guard crabs that live in its filaments and nip at nearby corals and grazers. The crabs and the alga's chemical defenses together keep it from being eaten.

Caring for Maiden's Hair Algae

Attach Maiden's Hair Algae to rock or rubble, where it grows as a low tuft rather than rooting in sand. It is reef safe but can spread when conditions suit it. Many keepers site it in a refugium or on a dedicated rock instead of loose in a mixed reef.

It wants strong light and notably high flow, more current than most refugium macroalgae, to keep its fine filaments clean. It needs no added CO2 and feeds from the water, taking up nitrate and phosphate. Keep it at 73 to 81°F (23 to 27°C) with a pH of 8 to 8.4.

It grows at a medium pace to about 3.1 in (8 cm). It is undemanding to feed but fussy about getting enough flow and light. Its chemical defenses mean cleanup crews will not keep it trimmed for you.

Good to know

Maiden's Hair Algae is Chlorodesmis fastigiata, a coenocytic siphonous green alga whose filaments branch dichotomously. It produces chlorodesmin, a diterpenoid feeding deterrent that makes it unpalatable to most reef herbivores. Because of that, it is often left untouched even in heavily grazed reef zones. Unlike Caulerpa, it is not prone to the same holocarpic crash.

In the wild

Maiden's Hair Algae grows on shallow tropical Indo-Pacific reefs, including Palau, Guam and the Great Barrier Reef. It forms dense, turf-like clumps of fine, forking filaments that look like soft grass or hair. It anchors to rock and coral rubble in bright, high-flow zones from the surface down to around 60 meters.