Chaetomorpha

Chaetomorpha linum

Also known as Chaeto, Spaghetti algae, Green hair algae (macro), Chato

SaltwaterMacroalgaeCuttings

Chaetomorpha (Chaetomorpha linum) — no rights reserved · cc0

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Growth rate: Fast
Placement: Floating
Type: Macroalgae
Temperature: 72–81°F (22–27°C)
pH: 8.0–8.4
Max height: 7.9 in (20 cm)
Spread: 11.8 in (30 cm)
Nutrient uptake: Water column
Growth region: Submersed
Difficulty: Beginner
Origin: Cosmopolitan; found in marine and brackish waters worldwide
Family: Cladophoraceae

Overview

The workhorse of nutrient export. Chaeto is kept in a lit refugium or sump where it strips nitrate and phosphate straight from the water column, competing out nuisance algae in the display. It wants medium to strong full-spectrum light and gentle tumbling flow so the whole ball rotates and stays clean. You physically remove a portion of the mass every week or two, and that harvest is what actually exports the nutrients from the system. Its dense tangle also shelters copepods and amphipods that feed the tank.

In the wild

A cosmopolitan green macroalgae from coastal marine and brackish waters, where it forms free-floating tangled masses rather than attaching to a substrate. It tolerates a wide range of conditions and is a staple of the reef refugium.

Good to know

Chaetomorpha linum is a filamentous green alga in the family Cladophoraceae. Its stiff, wiry filaments give it a coarse, fishing-line texture that resists being eaten by most tank inhabitants. It grows as an unattached ball or mat and spreads purely by fragmentation, so any healthy piece continues to grow on its own.

Did you know

Because it never sends up reproductive structures the way Caulerpa does, chaeto has no sudden crash or go-sexual event to worry about; a rotating ball just keeps growing, which is a big reason it became the default refugium macroalgae.