Marine & AlgaeIntermediate🌤️ Bright indirect

Halimeda (money plant)

Halimeda sp. · also called Money plant, Money algae, Cactus algae, Halimeda

🐾 Pet-safe

Generally non-toxic to cats and dogs.

Halimeda is a calcified green macroalgae made of stacked coin-shaped segments (hence "money plant") that grows like a small green cactus. It deposits calcium carbonate, so it draws down calcium and alkalinity, and looks attractive in both display and refugium settings.

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Quick facts

Category	Marine & Algae
Family	Halimedaceae
Native origin	Tropical reefs worldwide - Caribbean, Indo-Pacific, and Red Sea coral lagoons and rubble zones
Care difficulty	Intermediate
Light	Bright indirect
Pet toxicity	Pet-safe

Light

Wants moderate-to-strong reef lighting (medium-high aquarium light / good PAR) to support calcification and growth. Refugium or display reef LEDs both work; better light yields denser, healthier segments. Mapped to bright lighting needs.

Water

Reef parameters: 23-27 C (74-80 F), salinity ~1.025 SG, pH 8.1-8.4. Because it is calcifying, it needs well-maintained calcium (~400-450 ppm), alkalinity (8-11 dKH), and magnesium (~1300 ppm); it competes with corals for these. Less aggressive at nutrient export than chaeto but still uses some nitrate/phosphate. No CO2 (marine).

Soil & potting

Attaches to rock and rubble with a small holdfast, or roots loosely into sand in the wild. In the aquarium it is usually placed on or wedged into rock; the holdfast is not buried in nutrient substrate. No root tabs or aquasoil - it feeds from the water column and calcifies from dissolved minerals.

Environment — humidity, temperature, placement

Submersed only. CO2 not used (marine). Moderate flow keeps detritus off the segments. Good for display reef tanks as well as refugiums. Place midground/foreground where it gets adequate light. Resists grazing better than soft macros because of its calcified, gritty texture.

Propagation

Grows by adding new segments at the tips and branching. Propagate by cutting or breaking off a healthy branched section and securing it to rock; new holdfasts and segments will form. Can also drop segments that re-root.

Toxicity detail

Safe and reef-friendly; its calcified, somewhat distasteful tissue means most fish and invertebrates leave it alone, making it useful in herbivore tanks. Not invasive or regulated in aquarium contexts. Old/dying segments bleach white and should be removed.

Growth stages

How this plant changes through its life — each stage often has its own care, diet and space needs.

Photo coming soon

Spore / recruit

Aquatic plants and macroalgae establish from spores, seeds, or drifting fragments that settle and attach to substrate or rock. Many freshwater aquarium plants and marine macroalgae also spread readily from a detached piece that takes root or holdfast.

Photo coming soon

Young growth

Young growth puts out its first blades, fronds, or leaves and anchors with roots or a holdfast. Submersed plants may look different from their emersed form, and growth speeds up as the plant adapts to the water's light and nutrients.

Mature

A mature aquatic plant or macroalga reaches its full size and characteristic shape, forming the dense growth, runners, or fronds typical of the species. Established plants spread to fill space and can be divided or trimmed to propagate.

Sources

Halimeda - Wikipedia (encyclopedia)
Halimeda (Money Plant) Macroalgae Care - Reef2Reef (care guide)