Actinodendron plumosum – Hell’s Fire Anemone
Actinodendron plumosum was first described by Haddon in 1898. This anemone belongs to the family Actinodendridae. The genus name Actinodendron is derived from the Greek ‘aktis’ (ray) and ‘dendron’ (tree), which refers to the tree-like structure of the tentacles. The species name plumosum means ‘feathered’ in Latin, which refers to the anemone’s fringe-like tentacles. Their common name is Hell’s Fire Anemone or Branching Anemone.
Synonyms: Actinodendron alcyonidium.
Description
Actinodendron plumosum has a disc that can reach a diameter of 30 cm. The tentacles are strongly branched and can reach a length of 12 centimeters, giving the anemone a fringed, almost coral-like appearance. The color varies from light yellow-green, light brown to brown, light green to gray.
This anemone lives in symbiosis with commensal shrimps such as Ancylocaris brevicarpalis and Ancylomenes tosaensis. The shrimps find protection between the tentacles of the anemone, while the anemone benefits from the cleaning services of the shrimps.
Biotope
Actinodendron plumosum is found in tropical waters of the Indo-Pacific region, including the western central Pacific, New Caledonia, Palau, and the Great Barrier Reef. They inhabit sand flats, lagoon sands, and Halimeda patches, often buried in the sand with only their oral disc and tentacles visible. Their natural habitat consists of a calm, protected environment with minimal turbulence and a sand or coral rubble bottom.
Diet
In the wild, Actinodendron plumosum feeds on zooplankton and small fish that get entangled in their stinging tentacles. In an aquarium, they should be supplemented with small pieces of fish, shrimp or special anemone food. It is advisable not to give large pieces of food, as this can lead to water pollution.
The Aquarium
The aquarium for Actinodendron plumosum should be at least 200 liters, and larger if you want to keep multiple specimens. The aquarium should be set up with sand as a substrate and some rocks or coral rubble to mimic a natural environment. This anemone likes a moderate current and does not need strong lighting. The water parameters should be stable with a temperature between 24-28°C, a pH of 8.1-8.4, and a salinity of 1.023-1.025.
This anemone is very stinging and can harm other inhabitants in the aquarium. It is best to keep them with species that are resistant to their stings, such as certain shrimps and fish that do not come near the anemone.
Walking
Actinodendron plumosum can move, especially when the conditions in the aquarium are not ideal. They usually move to find a better place with suitable current and light. To prevent this, you should provide stable water parameters and a suitable habitat.
Toxic to humans
Is this anemone poisonous to humans? Yes, Actinodendron plumosum, also known as the Hell’s Fire Anemone, is toxic to humans. This anemone can cause severe and painful stings due to the nematocysts in its tentacles. The nematocysts contain two types of toxins: spirocysts and basitrichous isorhizas, with the basitrichous isorhizas being responsible for most of the poisonous effects.
How do the toxins work?
The nematocysts of Actinodendron plumosum contain a complex venom consisting mainly of basitrichous isorhizas. These nematocysts have a thick, double-walled capsule and a spiral tube that is expelled when touched. The venom causes an immediate stinging pain, followed by a burning sensation, redness, and swelling. The venom probably contains 5-hydroxytryptamine (serotonin), a substance that causes pain and releases histamine, which causes vasoconstriction or vasodilation depending on the dose and the area affected.
Symptoms of a sting:
- Immediate symptoms: A sharp stabbing pain, similar to a bee sting, followed by a burning sensation, redness, and swelling.
- Later symptoms: Petechial hemorrhages, ecchymosis, local necrosis, and ulceration. In severe cases, secondary infections may occur.
- General symptoms: Fever, chills, malaise, abdominal pain, nausea, vomiting, headache, extreme thirst, and exhaustion.
Treatment of a sting:
- Direct measures:
- Immediately rinse the affected area with vinegar or hot water to reduce nematocyst activity.
- Use soap, alcohol, sunscreen, oil, or other available material to inactivate the nematocysts.
- Remove the nematocysts as soon as possible with a towel, cloth, seaweed, stick, or a handful of sand.
- Medical treatment:
- Topical or oral cortisone preparations may be helpful.
- Oral antihistamines and topical antihistamine creams may help relieve urticarial lesions and symptoms.
- In case of severe reactions, it is advisable to seek medical attention for further treatment and monitoring.
Prevention:
- Avoid contact with the anemone by wearing protective diving clothing such as good quality leather, heavy canvas, plastic, or rubber gloves.
- Use caution when wading or swimming in waters where Actinodendron plumosum occurs, as this anemone can be difficult to identify because it resembles a moss-covered rock or piece of sponge.
Reproduction
In the wild, Actinodendron plumosum reproduces by releasing eggs and sperm into the water, where fertilization occurs. In an aquarium, they can sometimes split, but this rarely happens without human intervention. Manual splitting of the anemone can also be attempted, but this requires experience and care.
Particularities
A unique feature of Actinodendron plumosum is their ability to retract completely into the sand when disturbed, making them virtually invisible. They also have a very powerful and painful sting, making them one of the more dangerous anemones to deal with.
Conclusion
Actinodendron plumosum is a fascinating but challenging anemone to keep in an aquarium. They require specific conditions and can be dangerous to other inhabitants and the aquarist themselves. Therefore, This anemone is more suitable for experienced aquarists familiar with caring for poisonous species.
Video
Author
John de Lange
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