AquaticCare difficulty: AdvancedLegal complexity: Low

Hell's fire anemone

Actinodendron · also called Hell fire anemone, Hellfire anemone, Fire anemone, Tree anemone

Hell's fire anemones are dangerous to people: the sting brings sharp pain and burning, and it can go on to swelling, ulceration and tissue death. The real animals are Actinodendron, burrowers in sand whose long, forked tentacles resemble little trees, but the trade name is loose, and references disagree on whether it belongs to A. arboreum or A. plumosum, so this page stays at genus level. Treat any identification as provisional, and leave these animals to experienced keepers.

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.

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Quick facts

Size	Sand-burrowing body with long, branched tentacles, about 15-30 cm across when spread. Size varies with the species, which is rarely known.
Lifespan	—
Social needs	solo
Native region	Indo-Pacific
Origin	Old World
Climate	Tropical
Water type	Marine
Family	Actinodendridae
Genus	Actinodendron

Part of the Sea Anemones

Stinging, sessile cnidarians ranging from clownfish-hosting giants to nano-sized carpet species. Many are demanding, mobile, and can sting corals or be drawn into pumps — careful placement and rock-stable water are essential.

Beaded sea anemone Bubble tip anemone Carpet anemone Christmas anemone Condy anemone Haddon's carpet anemone Hemprich's sea anemone Long tentacle anemone Magnificent anemone Mertens' carpet anemone Mini Maxi Anemone Pizza anemone Rock flower anemone Sebae Anemone +2 more →

Color & pattern variants

Natural variants occur in the wild; selectively bred (man-made) variants were developed in captivity.

Natural

Crimson Hell's Fire Anemone →

Named for its crimson colour.

Red and Green Hell's Fire Anemone →

Named for its red and green colouring.

Red and Orange Hell's Fire Anemone →

Named for its red and orange colouring.

Ultra Rainbow Hell's Fire Anemone →

A hobby colour name. No fuller description is on record.

Yellow Trunk Hell's Fire Anemone →

Yellow trunks with brown tufts.

Highlighter Yellow Hell's Fire Anemone →

Named for its bright highlighter yellow colour.

Habitat & enclosure

Only consider one in an established tank with strong light, good flow and deep sand for the stalk, kept on its own and well clear of corals. In the wild these anemones live in sandy areas, lagoon sand and among seagrass across the Indo-Pacific, down to about 28 m.

Keep stable reef water: SG about 1.025, pH 8.1-8.4. One reef reference lists about 27-29 °C for A. plumosum.

Substrate

Provide deep sand so the stalk can sit well below the surface and the animal can withdraw fully. Keep the area around it free of rock work you will need to reach into.

Equipment & setup

Use strong reef lighting and good flow. Keep long tongs and sturdy gloves with the tank, and fit a secure cover so hands and pets cannot reach the water by accident.

Diet

Its reliance on light is not well documented. One reef reference lists zooxanthellae and light among its food, along with mysis and zooplankton, but no primary source checked confirms this, and the species in a tank is seldom known. Cover both: give strong light and offer small meaty foods such as mysis with long tongs, never by hand. No source gives a feeding schedule.

Behavior & temperament

The tentacles fork like little trees or broccoli, and a disturbed animal can vanish under the sand in moments. Animals under this name come in two quite different shapes: branches like little trees on tall trunks, and a thick, low carpet of forked tufts dotted with small ringed spheres. That second shape may not belong to Actinodendron at all. Anemone shrimp sometimes live on these animals.

Health

Dangerous to people. The name comes from the serious skin injuries it inflicts. A sting hurts at once, with sharp pain like a bee's, and burning, swelling and ulcers follow; some victims suffer tissue death and fever. There is no specific antidote, so seek medical care if stung. Small tentacle fragments can reportedly break off and still sting, including when the animal pulls into the sand. It will also harm corals and other tankmates it touches.

Tips, DIY & hacks

This animal can seriously injure you. Put on gloves for every tank job, keep bare skin off it, and get medical care after any sting. Children and pets must not be able to reach it. Plan every tank job around it, and hold it well apart from corals. One reef reference rates A. plumosum as not suitable for aquariums at all, so think hard before taking one on.