Cryptonemia

Cryptonemia · also called Gorgonian-Encrusting, Rose Petal, Cryptonemia floridana

Cryptonemia is a red macroalgae with thin blades. C. crenulata has frilly, serrated blades in red to orange and is recorded growing on gorgonians and reef rock across the Caribbean. It is often confused with Neurymenia. Keepers have little experience with it, and care data comes mainly from one hobby guide. Rose Petal (C. floridana), formerly Halymenia floridana, has fleshy, delicate blades and is notably fragile when moved.

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	Halymeniaceae
Native origin	Caribbean and Gulf of Mexico to Brazil
Care difficulty	Intermediate
Light	Low light
Pet toxicity	Toxicity unknown

Light

One hobby guide reports that it tolerates low light well, which is unusual among kept red algae, and color runs from red to orange depending on collection depth. Start at low to moderate reef lighting and raise it slowly. Keepers have little other data on its light needs.

Water

Standard reef parameters: 23-27 C (74-80 F), salinity ~1.025 SG, pH 8.1-8.4. No specific needs are recorded. Keep salinity and temperature stable, and keep nitrate and phosphate measurable. It grows slowly, so water tests are a better guide than its looks.

Soil & potting

In the wild it grows on living and dead gorgonians, reef rock, ledges, sponges and other corals rather than in sand. In a tank, tie a blade base to rock or rubble with line, or wedge it into a ledge. Keep it off any living corals and gorgonians you want to protect.

Environment — humidity, temperature, placement

Give it decent water movement, which hobby reports rate as moderate to high, on a shaded ledge or lower spot in a display. Standard reef temperature, 23-27 C (74-80 F), suits a Caribbean species. Keepers have little other data, so watch how the blades respond after placement.

Propagation

Slow growing. Hobby reports describe dividing a plant into smaller pieces and securing them to rock, and that is the only recorded method. Take small sections from a healthy plant, tie them down and leave them undisturbed. Expect little visible change for some time.

Toxicity detail

No toxicity data for tank animals was found, so the rating stays unknown. No grazing deterrent is recorded. Since it grows on gorgonians and corals in the wild, watch for it settling on them in a tank and trim it back, though no harm to corals has been documented.

Varieties & cultivars

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

Natural forms2

Rose Petal

Cryptonemia floridana. A reddish-pink red alga, formerly Halymenia floridana, with fleshy, delicate blades like rose petals. It is notably fragile when moved.

Handle it as little as possible, since its soft blades damage easily.

Gorgonian-Encrusting

Cryptonemia crenulata. A red alga with thin, frilly blades. Its trade name suggests it settles on gorgonians.

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