Digenea

Digenea · also called Fuzzy Antler, Red seabroom

Digenea is a slow-growing red macroalgae whose branches are covered in short, fine filaments that give it a fuzzy look. D. simplex is the original source of kainic acid, a potent nerve-acting compound. It is not often kept, and keepers have little experience with its care.

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	Rhodomelaceae
Native origin	Tropical seas of the Indo-Pacific and Atlantic
Care difficulty	Intermediate
Light	Medium light
Pet toxicity	Toxicity unknown

Light

Keepers have little experience with its light needs. Wild plants grow in the intertidal and shallow subtidal, so moderate to strong reef light is a fair start. Because it grows so slowly, it can take a long time to show whether the light suits it, so make changes in small steps.

Water

Standard reef parameters: 23-27 C (74-80 F), salinity ~1.025 SG, pH 8.1-8.4. No specific needs are recorded. Growth is very slow, so do not read a lack of change as a problem. Keep salinity and temperature steady, and keep nitrate and phosphate measurable rather than stripped out.

Soil & potting

Attaches to coral fragments, rocks and other hard surfaces rather than rooting in sand. In a tank, tie a piece to rubble or wedge it into rockwork and keep the base out of the sand. Keepers have little record of how quickly cuttings attach, so leave it undisturbed once placed.

Environment — humidity, temperature, placement

Wild plants live in calm bays and open lagoons as well as on shallow hard bottoms. Steady moderate flow at standard reef temperature, 23-27 C (74-80 F), is a cautious start in a display or macroalgae tank. The fine filaments may hold debris, so avoid dead spots.

Propagation

Growth is very slow, so give a cutting plenty of time before expecting change. Keepers have little record of propagating it. Trim only a small branch from a healthy plant and tie it to rubble. It is best treated as a long-term specimen rather than a plant to harvest.

Toxicity detail

No source covers cats or dogs, so the rating stays unknown. It produces kainic acid, a neurotoxin and excitant that may serve as a chemical defense; the alga has long been used against parasitic worms. No harm to tank animals is documented, but do not offer it as fish food. No coral smothering risk is recorded.

Varieties & cultivars

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

Natural forms1

Fuzzy Antler

Digenea simplex. A slow-growing red alga with fine filaments along its branches that give it a fuzzy look. It is not often kept.

Growth is very slow, so give a cutting time before expecting much change.