Chaeto (Spaghetti Algae) Chaetomorpha (+10 cm Ball)

Quick facts

Identity

Also known as

Chaeto; Spaghetti algae

Synonyms

Chaetomorpha linum

Environment

Freshwater

Native to

Cosmopolitan, coastal marine and brackish waters worldwide

Habitat

Coastal marine and brackish waters, forming free-floating tangled masses rather than attaching to substrate

Sourcing

Aquacultured

Conservation

Not Evaluated

Care

Care level

Easy

Growth form

Macroalgae

Max height

4 – 12 in (10 – 30 cm)

Spread

12 in (30 cm)

Growth rate

Fast

Placement

Midground

Water

Temperature

72 – 81 °F (22 – 27 °C)

pH

8.0 – 8.4

dKH

7 – 12 dKH

PAR

100 – 250 PAR

Flow

Moderate-High

Light

High

CO₂

Not needed

Planting

Substrate

Not needed

Feeds from

Water column

Fertilizer needs

High

Colors

Green

Feeding & breeding

Propagation

Cuttings

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Care guide

Overview

Tumbles in loose, tangled strands of wiry green filaments rather than attaching anywhere, rotating through refugium flow as it strips nitrate and phosphate from the water column. Supplied as a roughly 10 cm starting ball, it grows quickly under strong light and needs periodic harvesting to keep the whole mass photosynthesizing evenly and prevent shaded, dying interior strands.

Care

Chaeto is grown almost exclusively in a lit refugium or sump rather than the display, where it is left loosely tumbling in moderate to strong flow so the whole mass rotates and stays clean. It needs full-spectrum light for 8-12 hours daily, often run on a schedule opposite the display tank to help offset nighttime pH dips. Being wiry and fast-growing, it tolerates a wide range of temperature and salinity, and generally shrugs off poor water quality better than most other macroalgae.

Planting & trimming

Chaeto is not planted or attached to substrate; it is simply placed loose in a refugium chamber or algae reactor where flow keeps it tumbling and exposed to light on all sides. A ball roughly 10 cm or larger is a practical starting mass for a small to medium refugium. Harvest a portion every one to two weeks once established, since physically removing biomass is what actually exports the nutrients it has absorbed.

Fertilizing

No dosed fertilizer is needed since chaeto pulls nitrate and phosphate directly from aquarium water through its filaments. Growth stalls or turns pale and brittle when nutrients run too low, which is common in ultra-low-nutrient reef systems, and can be corrected by allowing nitrate and phosphate to build slightly or dosing a small amount. Adequate iron and trace elements in the water column support healthy deep green coloration, though this is rarely a limiting factor in a typical reef system.

Propagation

Propagation is simply fragmentation: any healthy piece torn or cut from the main mass continues growing independently. Leftover trimmings from routine harvesting can be used to seed a new refugium or shared with other hobbyists. No special technique is required beyond keeping cut fragments in adequate light and flow.

Problems

A healthy mass stays a rich green and steadily increases in bulk; algae that pales, yellows, or turns brittle and falls apart is usually signaling a lighting or nutrient imbalance. Because it spreads only by fragmentation and never goes sexual or crashes the way Caulerpa can, sudden die-offs are uncommon if flow and light are adequate. Dense, overcrowded masses can shade their own interior, so periodic harvesting keeps the whole ball photosynthesizing evenly.

Sources

1. Chaeto in the Refugium: Care & Troubleshooting | AlgaeBarn
2. Chaetomorpha care: light, CO2 and placement · TankBud
3. How To Care For Chaetomorpha - Bulk Reef Supply
4. About Green Alga Chaetomorpha | Macroalgae | The Algae Lab - AlgaeBarn

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