Rhodymenia

Rhodymenia · also called Ruby Red Turf

Rhodymenia is a genus of red macroalgae found mainly in temperate to cool water. The kept form, Ruby Red Turf, is a tiny, bushy alga that spreads low over rock and substrate rather than forming upright fronds. Keepers have little experience with it, and one reference warns plants often decline over time.

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	Rhodymeniaceae
Native origin	Mostly temperate to cool seas worldwide; kept form unrecorded
Care difficulty	Intermediate
Light	Medium light
Pet toxicity	Toxicity unknown

Light

Keepers have little experience with its light needs, so start with moderate reef lighting and change it gradually. Red macroalgae in general do not need extreme light and often color well under full-spectrum or slightly bluer lamps. Watch a new patch for fading, and hold the light steady.

Water

Standard reef parameters: 23-27 C (74-80 F), salinity ~1.025 SG, pH 8.1-8.4. No specific needs are recorded. Stable conditions matter, and red macroalgae generally do best in good, mature systems. Much of the genus lives in cool water, so avoid the top of the range until you know how it responds.

Soil & potting

Spreads over rocks and substrate in a low, bushy crust, so it needs a hard surface rather than loose sand. Start it on the rubble or rock it came on and set that where you want it to grow. Keepers have little record of how quickly it creeps onto new surfaces.

Environment — humidity, temperature, placement

Moderate flow in a display or macroalgae tank at standard reef temperature, 23-27 C (74-80 F), is a cautious start. One reference lists a warm range for kept plants, but most of the genus lives in cooler water, so treat the identity of a tropical turf under this name with some caution.

Propagation

It spreads on its own across rock as a low turf. A reference notes these algae often grow quickly when first brought in on live rock and then decline, with many keepers unable to hold them long term. To keep a patch going, move small coated chips to new rock while it is healthy.

Toxicity detail

No toxicity data for tank animals was found, so the rating stays unknown. No grazing deterrent is recorded. As a low turf it could creep up to corals, though no harm has been documented. Trim back any growth that reaches coral bases and watch how it behaves in your tank.

Varieties & cultivars

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

Natural forms1

Ruby Red Turf

Rhodymenia sp. A very small red alga that spreads over rocks and substrate in a bushy crust. It stays low, forming a turf rather than upright fronds.

Little is recorded about its care, so keep conditions stable and change lighting gradually.