Nemastoma

Nemastoma · also called Rose Petal Nemastoma, Orange-Tipped Nemastoma, Finger Nemastoma, Pink Thorny Nemastoma, Thin Nemastoma

Nemastoma is a genus of very thin, gelatinous red macroalgae that feel slippery in the hand. Kept forms come in red, orange, yellow and pink, and one develops fluorescent orange tips. Cuttings struggle to form a holdfast, so these are not beginner species, and they are 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	Nemastomataceae
Native origin	Recorded from the Caribbean, Atlantic and Indian Ocean; kept forms rarely named to species
Care difficulty	Advanced
Light	Medium light
Pet toxicity	Toxicity unknown

Light

A reference entry for a related species calls it hardy even in low light, while hobby reports suggest moderate to high light. Moderate reef lighting is a fair middle ground. The tips of Orange-Tipped Nemastoma glow under actinic light, so include some actinic to enjoy them.

Water

Standard reef parameters: 23-27 C (74-80 F), salinity ~1.025 SG, pH 8.1-8.4. A reference entry for a related species stresses excellent water quality and says iodine additions may help. Keep nitrate and phosphate measurable, and avoid sudden swings in salinity.

Soil & potting

Never glue it; the tissue is too slippery and gelatinous. Tie it down with fishing line or hold it loosely with a clear zip tie against rock or rubble. Cuttings are slow to form a holdfast, so keep the tie in place and avoid disturbing the piece while it settles.

Environment — humidity, temperature, placement

Natural habitats range from sheltered spots with strong current to rough coastlines, so moderate to fairly turbulent flow suits it. It works in a display or a refugium at standard reef temperature, 23-27 C (74-80 F). Finger Nemastoma gives shelter to copepods and amphipods.

Propagation

Reported propagation is by fragmentation, but cuttings are slow to attach. Trim a small section, tie it to rubble with fishing line or a loose clear zip tie, and leave it alone. Forms such as Finger and Thin Nemastoma are fragile when moved, so take cuttings sparingly.

Toxicity detail

No toxicity data for tank animals was found, so the rating stays unknown. A reference entry lists a related species as likely suitable for reef and fish-only tanks, and kept forms shelter copepods and amphipods. No grazing deterrent or 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 forms5

Rose Petal Nemastoma

Nemastoma sp. A very thin, gelatinous Nemastoma that feels slippery to the touch. Cuttings are slow to form a holdfast.

Never glue it: tie it down with fishing line or hold it loosely with a clear zip tie. Not a beginner species, and somewhat fragile when moved.

Orange-Tipped Nemastoma

Nemastoma sp. A very thin, gelatinous Nemastoma, slippery to the touch, whose tips develop a fluorescent orange glow under actinic light. Cuttings are slow to form a holdfast.

Never glue it: tie it down with fishing line or hold it loosely with a clear zip tie. Not a beginner species, and somewhat fragile when moved.

Finger Nemastoma

Nemastoma sp. A thin, gelatinous Nemastoma, slippery to the touch, in red, orange or yellow. It suits both display tanks and refugiums, where it gives shelter to copepods and amphipods. Cuttings are slow to form a holdfast.

Notably fragile when moved and slow to attach, so secure it gently and leave it undisturbed.

Pink Thorny Nemastoma

Nemastoma sp. A very thin, gelatinous Nemastoma that feels slippery. As the name suggests, it has a pink, thorny look, and cuttings are slow to form a holdfast.

Never glue it: tie it down with fishing line or hold it loosely with a clear zip tie. Not a beginner species, and somewhat fragile when moved.

Thin Nemastoma

Nemastoma sp. A very thin, gelatinous Nemastoma that feels slippery. Cuttings are slow to form a holdfast.

Notably fragile when moved and slow to attach, so secure it gently and leave it undisturbed.

Sources

Nemastoma, World Register of Marine Species (web)
Nemastomataceae, World Register of Marine Species (web)
Nemastoma gelatinosum, Saltcorner Aquarium Library (web)
Nemastoma, Integrated Taxonomic Information System (web)