Caulerpa mexicana Care Guide
Caulerpa mexicana is a feather-shaped marine green macroalga common on Caribbean reefs, used in refugiums to export nitrate and shelter inverts.
Compiled by Aquairi from published sources · Published · Updated
Overview
Caulerpa mexicana is a marine green macroalga in the family Caulerpaceae with flat, feather-like (pinnate) fronds rising from thick runners. Like all Caulerpa it is a coenocytic single-celled organism. It is valued in refugiums for fast nutrient uptake and as shelter for small invertebrates.
Taxonomy
- Family: Caulerpaceae
- Genus: Caulerpa
- Scientific name: Caulerpa mexicana Sonder ex Kützing, 1849 (WoRMS AphiaID 144468)
- Common synonyms: Feather caulerpa
Habitat
The species occurs in tropical and subtropical seas, including the Caribbean Sea and Gulf of Mexico, where it grows in shallow water along rocky shorelines, in seagrass beds and on coral reefs. Flat dark-green pinnate fronds arise from thick green rhizome-like runners; fronds typically reach about 15-30 cm.
Aquarium requirements
- Placement: midground / refugium
- Temperature: 22-28 °C (72-82 °F)
- Specific gravity: 1.024-1.026
- pH: 8.0-8.4
- dKH: 8-12
- Lighting: medium
- Role: nutrient (nitrate/phosphate) export
Growth and care
Caulerpa mexicana is fast-growing and easy, absorbing nitrate efficiently in a refugium. Harvest regularly and keep lighting consistent to reduce the chance of the alga going sexual. The genus produces defensive secondary metabolites such as caulerpin.
Propagation
Propagation is by division of runners and fragmentation; pieces with intact runner tissue re-establish quickly.
Propagating Caulerpa mexicana: Dividing the Marine Feather Macroalga
Overview
Caulerpa mexicana is a marine green macroalga with flat, feather-shaped fronds rising from a creeping stolon (runner). Remarkably, an entire Caulerpa is a single cell containing many nuclei, making it one of the largest single cells in the world. It is widely kept in reef refugiums to export excess nitrate and to provide shelter for marine invertebrates.
Because Caulerpa anchors with rhizoids on its stolon rather than with true roots, it is not propagated like a stem plant with substrate cuttings. Instead you divide the running stolon, and each fragment regenerates on its own.
Propagation Method
Caulerpa reproduces primarily through fragmentation. When a piece breaks off, it regenerates directionally, growing rhizoids at the bottom and fronds at the top. This makes simple division of the stolon the reliable, fast way to multiply it.
Step-by-Step Division
- Identify a vigorous, green stolon running across the refugium or rock.
- With clean scissors, cut a stolon segment carrying several fronds and rhizoids.
- Avoid tearing — a clean cut leaves both halves able to regenerate.
- Wedge the fragment into rubble or rock crevices so the rhizoids can re-anchor.
- Keep flow gentle at first so the new piece is not swept away before it attaches.
Conditions for Healthy Growth
Caulerpa tolerates a wide range of temperatures and grows quickly even under relatively adverse conditions. In aquaria it suits standard reef parameters: roughly 22–28 degrees C, marine salinity, and pH around 8.0–8.4. It absorbs nutrients both from the water column and through its rhizoids, which is exactly why it works as a nutrient-export macroalga. Medium lighting in a refugium drives steady growth.
Maintenance
Harvest regularly to keep growth vegetative. A practical routine is to remove about half of the mass every couple of weeks, taking out the older portions first. Frequent harvesting both exports nutrients and reduces the risk of a sexual event.
Common Challenges
Beyond the sexual crash, the chief concern is invasiveness. Caulerpa species spread aggressively through rhizoid extension and fragmentation and are invasive in several seas, so never release fragments or refugium water into the wild and dispose of trimmings responsibly.