Sarcodiotheca

Sarcodiotheca · also called Succulent Seaweed, Red String Seaweed

Sarcodiotheca is a fleshy, branching red macroalgae. S. gaudichaudii resembles a bulkier, stiffer Gracilaria, which explains the name Succulent Seaweed. Wild plants come mainly from the cool Pacific coast of North America, so it does not suit a tropical tank, and one reference lists it as not suitable for aquarium keeping.

Educational only. Some KinStation entries are reviewed by licensed veterinarians, but none can replace an in-person exam. Always consult a licensed veterinarian or board-certified specialist for diagnosis, treatment, or any decision affecting your pet's health.

Quick facts

Category	Marine & Algae
Family	Solieriaceae
Native origin	Pacific coast of the Americas: Alaska to Baja California, with records from Peru and Chile
Care difficulty	Advanced
Light	Medium light
Pet toxicity	Toxicity unknown

Light

Keepers have little experience with its light needs. Its Gracilaria-like habit suggests moderate reef lighting is a fair start, and wild plants grow from the lower intertidal into the subtidal. Raise intensity slowly, and watch for color loss, which may mean the light is too strong.

Water

A cool-water Pacific alga that does not suit a tropical tank, so do not run it at standard reef temperature. Wild S. gaudichaudii ranges from Alaska to Baja California, and one reference lists it as not suitable for aquarium keeping. No tested temperature limit is recorded. Salinity ~1.025 SG and pH 8.1-8.4 are a fair start. Keep nitrate and phosphate measurable.

Soil & potting

Wild plants grow on rocks, often embedded in sand, and on smaller stones and shells. In a tank, tie a branch to a small stone or shell and let it rest on the sand surface, or fix it to rubble. Keepers have little record of how it attaches, so avoid disturbing it once placed.

Environment — humidity, temperature, placement

It does not belong in a warm reef display: this is a cool-water Pacific alga that does not suit a tropical tank, and one reference lists it as not suitable for aquarium keeping. Moderate flow in a cool refugium or macroalgae tank is a cautious start. Keepers have little data, so watch it closely.

Propagation

Keepers have little record of propagating it. A firm, branching alga like this can likely be trimmed and tied to rubble in the same way as Gracilaria, but that has not been confirmed. Start with a small cutting from a healthy plant and leave the parent mostly intact.

Toxicity detail

No toxicity data for tank animals was found, so the rating stays unknown. No grazing deterrent or coral smothering risk is recorded. A stressed plant in warm water could break down and foul the tank, so remove any pale or softening tissue quickly. Never release it into the wild.

Varieties & cultivars

Natural forms are the wild species; cultivars are selectively-bred colour or variegation forms of the same plant.

Natural forms1

Succulent Seaweed

Sarcodiotheca gaudichaudii. A branching red alga much like Gracilaria, only larger, firmer and thicker. The fleshy build explains its name.

A cool-water Pacific alga that does not suit a tropical tank. A plant kept in a reef tank under this name may be misidentified.