The Hell’s Fire Anemone looks a lot like a coral, but beware of their much more powerful sting!

The Hell’s Fire Anemone Actinodendron plumosum looks more like a coral, but is actually a burrowing anemone. They bury their foot and body in the sand with only their oral disc and tentacles emerging. When disturbed they can retract their entire body into the sand and be virtually invisible.

The Actinodendron genus is a unique group of anemones that are basically in a class all their own. They look more like colonies of soft corals than actinides. Typically they have busy, branched long tentacles. The Hell’s Fire Anemone has tentacles with a leaf-shaped or feather-like appearance, thus they are also known as the Pinnate Anemone, Tree Anemone, and Branching Anemone.

The Hell’s Fire Anemone is one of the ‘stinging sea anemones’ in the Actinodendronidae family. This family consists of three genera; Actinodendron, Actinostephanus, and Megalactis, all of which are found only in the tropical waters of the Indo-Pacific. These anemones are so named ‘stinging sea anemones’ because of their capacity to sting humans badly.

Although all anemones have stinging cells, nematocysts found in their tentacles, the Hell’s Fire Anemone has a dangerous sting that is extremely powerful and is very painful. In fact, its toxin is so potent, it is reputed to even sting fish to eat. Another anemone from this group, the Bali Fire AnemoneMegalactis hemprichi, is similar in this regard and is also referred to as a Hell’s Fire Anemone.

Purchasing a Hell’s Fire Anemone, or any of the ‘stinging sea anemones,’ needs to be made with enough knowledge to protect yourself and your other charges.They have a very different look from anything that is typically sold. They are very poisonous and the sting is very painful. Aquarists be warned and wear gloves when handling this genus. The sting from these anemones can damage and even kill other corals. The Hell’s Fire Anemone is also reputed to sting and eat fish. Keeping them in a species specific tank allows you and them to be happy.

For more about the types of Sea Anemone Species, see:
Sea Anemone – Tube Anemone

Hell’s Fire Anemone, Actinodendron plumosum, & Harlequin Crab Pair

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Up close and personal with some marine symbiosis!

The Hell’s Fire Anemone differs in a few ways from other anemones. While they need good light, a mature tank and good meaty foods, they do not play well with others. The Hell’s Fire Anemone will sting all other corals with a sting that is much more potent than many other anemones. This anemone will not host clownfish, only inverts, like for instance… Harlequin Crabs! They make a great addition to a species specific tank!

Hell’s Fire Anemone – Quick Aquarium Care
  • Minimum Tank Size: 50 gal (189 L)
  • Aquarist Experience Level: Intermediate
  • Temperament: Aggressive
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
  • Size of organism – inches: 12.0 inches (30.48 cm)
  • Diet Type: Carnivore
  • Suitable for Nano Tank: No

Habitat: Distribution / Background

The Hell’s Fire Anemone Actinodendron plumosum was described by Haddon in 1898, and is found in the tropical Indo-Pacific Ocean. This anemone is not on the IUCN Red List for endangered species. Some other common names this anemone is known by are Pinnate Anemone, Tree Anemone, and Branching Anemone.

The Actinodendron genus is a member of the Actinodendronidae Family, which was described by Quoy & Gaimard in 1833. There are currently 5 accepted species in this genus, including A. alcyonoideum, A. arboreum, A. glomeratum, A. hansingorum, and A. plumosum. They have a very potent toxin in their tentacles, have been known to sting divers quite badly.

The most common members of this genus are the Hell’s Fire Anemone, Tree Anemone Actinodendron arboreum, which was described by Quoy & Gaimard in 1833, and the Branching Anemone Actinodendron glomeratum, which was described by Haddon in 1898.

This genus lives singly in sandy and rubble covered bottoms on coral reefs, burrowed deep into the substrate with all but their tentacles showing. These anemones are found at depths of 1 – 65 feet (3 – 20 m). They use their very powerful and venomous cells or nematocysts found in their tentacles to sting and deflect any possible threats or attacks, as well as for capturing prey. It is unknown if the Actinodendron species have any predators.

  • Scientific Name: Actinodendron plumosum
  • IUCN Red List: NE – Not Evaluated or not listed


The Hell’s Fire Anemone can grow up to 12″ (30 cm). The Actinodendron genus has a pedal column that they bury in rubble or sand. They have many pairs of highly branched tentacles that make the them look more like a coral or a small tree than an anemone. It is unknown how long they live, in fact some anemones can be hundreds of years old in the wild, and in captivity have been known to last 80 years or more.

The color of the A. plumosum can be light yellowish green, tan, brown, light green or gray. The anemone can be monochromatic or a combination of these colors. Each tentacle varies in size and has more of a “frilly†look to it. From a distance it almost looks like soft coral, like a kenya tree. This anemone comes out at night and hides during the day.

Two other common Actinodendron species:

  • Tree Anemone A. arboreum has branching tentacles that are more erect and also covered with vesicles. The oral disc area is open, with the tentacles being around the margin.
  • Branching Anemone A. glomeratum can be greenish to gray in color. They are usually a mix of these colors. They lay flat on the sand with each tentacle having a space in between. Each tentacle has clusters of vesicles that look like a tiny forest of cauliflower covering it from top to bottom. This makes each one look like a fat, thick, lumpy protrusion. Each one, from a distance almost looks like an acropora branch.

The mouth should be closed and tight, and will open when hungry, having an oval look; yet a gaping mouth is a warning signal. The Actinodendron plumosum take food in, and expel waste through this same opening. They use their very powerful and venomous cells or nematocyst found in their tentacles to sting and deflect any possible threats or attacks, as well as for capturing prey.

  • Size of organism – inches: 12.0 inches (30.48 cm)
  • Lifespan: 80 years – It is unknown how long they live, but some anemones have lived more 100 years or more in captivity.

Difficulty of Care

The Actinodendron genus can be easy to care for yet, they do have lighting needs. They must also be in a large enough aquarium to satisfy their ultimate size. Putting an anemone in a new tank will result in failure. The tank should be at least 6 months old, though 9 t0 12 months is better, and stable before adding your new A. plumosum anemone. They are best kept in a species specific tank.

When choosing a Hell’s Fire Anemone, make sure the color is good, their mouth is not gaping open, and their foot and tentacles are sticky to the touch. They should be attached to something and make sure there is no damage to the foot area, often a result of pulling the anemone off its surface.

To transfer a Hell’s Fire Anemone from another aquarium, use a very thin blunt item, like a credit card, to get under the foot. Slowly nudging it away will get the anemone off the glass. If its attached to a rock, ideally you can simply purchase the rock as well. They are very poisonous and the sting is very painful, so aquarists be warned and wear gloves when handling this genus.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Intermediate

Foods and Feeding

The Hell’s Fire Anemone is a carnivore and will generally accept small meaty foods in captivity. Feed the anemone chopped silversides, shrimp, krill and mussels, and fresh chopped fish (from your grocery store), as well as frozen carnivore preparations. Feed 2 times a week to keep them healthy. The old adage that anemones should only be fed once a month is false and has lead to many deaths.

  • Diet Type: Carnivore
  • Flake Food: Occasionally – Depends on individual tastes of the anemone.
  • Tablet / Pellet: Occasionally – Depends on individual tastes of the anemone.
  • Live foods (fishes, shrimps, worms): – From marine sources as a treat.
  • Liquid Foods: – Liquid foods with larger zooplankton.
  • Meaty Food: All of Diet – Any and all finely minced marine flesh preparations.
  • Feeding Frequency: Weekly – Feed them twice a week.

Aquarium Care

Water changes of 10% bi-monthly or 20% a month are typical. Monitor your water quality for your particular situation and adjust your water changes accordingly. Waste production created by your anemone can be calculated in inches. Basically, every inch of anemone is equal to an inch of fish, so an average sized Hell’s Fire Anemone of 12″ produces a bioload equivalent to that of four 3″ fish or two 6″ fish.

Purigen and Poly-fiber are great products to help in maintaining water quality. Purigen is a synthetic polymer that removes soluble and insoluble impurities from water at an exceptionally high rate and capacity, helping to control ammonia, nitrites and nitrates. Poly-fiber can be cut and used in sumps, etc. A good protein skimmer is a must.

Although anemones are not as dependent on calcium as stony corals, magnesium and calcium is still needed to keep the pH and alkalinity stable and within the correct parameters. Additions of trace elements are suggested. Phosphates should be kept around 0.03 or less.

  • Water Changes: Bi-weekly – Water changes of 10% twice a month, or 20% a month are typical.
  • Calcium Levels: 380.0 – 450.0 ppm – Helps to balance alkalinity. Aim for 420 ppm, or 385 ppm if you are using Seachem calcium.
  • Alkalinity Levels: 7.0 – 11.0 dKH – (2.5 to 3.9 meq/L) Aim for 10 dKH (3.5 meq/l) for reef tanks.
  • Magnesium Levels: 1,250.0 – 1,350.0 ppm – Test magnesium levels and adjust before checking Calcium.
  • Strontium Levels: 5.0 – 15.0 ppm – Aim for 8 ppm.
  • Iodine Levels: – .030 to .060 ppm: Control is not recommended.

Aquarium Setup

The typical reef environment is what is needed for your Hell’s Fire Anemone. A mature 50-gallon tank that is at least 9 to 12 months old is advised to increase the successful life span of A. plumosum. They are not suited for small nano tanks, since it is hard to keep water quality high and due to their ultimate size. They need live rock and a deep sandy or crushed coral substrate to bury themselves into. The Hell’s Fire Anemone will bury its body in the sand and attach the foot to a hard surface under the substrate. It has the ability to retract into the sand until it’s virtually invisible.

They need good lighting and the water movement should be moderate. A good protein skimmer is a must. Once it is secured and settled, if it is happy it will stay put. If it isn’t happy and is moving around, be sure to check your checking your lighting and water quality. Also, make sure you are feeding it adequately. With all anemones it’s a good rule of thumb to have all of your pumps covered. Most good quality pumps have guards on them.

  • Minimum Tank Size: 50 gal (189 L)
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Amount
  • Substrate Type: Mix – Sand + Coral – They like a deep sandy or crushed coral substrate to bury into.
  • Lighting Needs: Moderate – normal lighting – Lighting should be moderate to high (normal to strong).
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
  • Specific gravity: 1.023-1.025 SG
  • Water Movement: Moderate
  • Water Region: Bottom – Generally situates itself on the bottom, but will settle where ever it is comfortable and happy.

Social Behaviors

The Hell’s Fire Anemones are aggressive and have a powerful sting that can kill nearby corals and fish. These are aggressive anemones because they can be mobile, although a contented anemone will often stay put once it has found a place to settle. If it starts moving around you need to check your aquarium parameters and feeding schedule to find out why it is unhappy.

They are not typically sold, and their propensity to eat your fish should deter a purchase for anything other than a species display tank. It has often been suggested to not put anemones in a reef environment since corals cannot move away from the stinging tentacles. Once you get your anemone situated and it has not moved for several months, it might be safe to add other corals.

After splitting, they will tolerate their own “clones,†but will kill other anemones. All anemones need to have their own space, otherwise there can be a “chemical” warfare between species. This will usually cause one to not eat, shrink and eventually die. Having excellent filtration and a large tank, (over 100 gallons) will usually allow 2 anemones at opposite ends to thrive. You can also build a natural blockade to help prevent them from wandering into each others “space”.

Besides stinging corals, they will sting and kill small fish, including clownfish because Hell’s Fire Anemones do not host them. Invertebrates, like snails and starfish, will know to stay away from the anemone. However, a very large tank is needed since these animals will constantly run into this anemone and could eventually die from the sting. In the wild, they do have a commensal relationship with some Periclimenes sp. of shrimp. They may also host the Harlequin Crab, like Bali Fire Anemone does, and that makes for an amusing display.

  • Venomous: Yes – The Hell’s Fire Anemone may roam and sting sessile corals.
  • Temperament: Aggressive
  • Compatible with:
    • Same species – conspecifics: Sometimes – They will only tolerate their own clones.
    • Anemones: Threat
    • Mushroom Anemones – Corallimorphs: Threat
    • Leather Corals: Threat
    • Zoanthids – Button Polyps, Sea Mats: Threat
    • Sponges, Tunicates: Threat
    • Shrimps, Crabs, Snails: Monitor – They have a commensal relationship with some Periclimenes sp. of shrimp and may host Harlequin Crabs.
    • Starfish: Threat
    • Feather Dusters, Bristle Worms, Flatworms: Threat
    • Clams, Scallops, Oysters: Threat
    • Snails: Threat
    • Sea Apples, Cucumbers: Threat
    • Urchins, Sand Dollars: Threat
    • Nudibranch, Sea Slugs: Threat
    • Copepods, Amphipods, Mini Brittle Stars: Threat
    • Stony Corals: Threat – is aggressive
    • Soft Corals: Threat – is aggressive

Sex: Sexual differences

No sexual difference in appearance is known.

Breeding / Reproduction

The Actinodendron species have not been bred in captivity. Anemones in general can multiply by sexual and asexual means. One way is using fission, which is when they actually split in half from the foot or mouth to form a clone, although the clone is its own animal, similar to twins. They will also reproduce using male and female sex glands or find another anemone of the opposite sex. This results in the production of ciliated planula larvae. This planula will eventually fall to the sea floor, develop a pedal disk, then begin to grow into a new anemone.

  • Ease of Breeding: Unknown – Has not been bred in captivity.

Ailments / Diseases

Hell’s Fire Anemones are usually disease free. Problems are pretty minimal unless your lighting, water movement, feeding and/or water quality is low or inadequate. In that case, your anemone will detach to look for “better conditions.” In general, if your anemone moves, it is not happy. This usually results in an unpleasant experience with a water pump.


The Hell’s Fire Anemone is rarely available to aquarists, and only suggested for a species specific tank.