Delicate Sea Anemone

The Delicate Sea Anemone is the black sheep of the family because it hosts only ONE type of Clownfish in the wild!

Unlike the other members of the Heteractis genus, very few adult clownfish are hosted by the Delicate Sea Anemone Heteractis malu. Most species of adult clownfish tend to shun it. However It will provide shelter to various juvenile clownfish passing through on their journey to find a more suitable host anemone for adulthood.

In nature the clownfish it is known to associate with is the Clark’s ClownfishAmphiprion clarkii (yet some report the Ocellaris ClownfishAmphiprion ocellaris also). In captivity it will host both the adult Clark’s Clownfish and Maroon ClownfishPremnas biaculeatus.

This anemone is quite decorative both in color and appearance. Though it is a runt in its genus, it still reaches up to 8 inches (20 cm) in diameter. Its short stubby tentacles are variable in color and size, but don’t reach more than 4 cm in length. Color can be white with purple, pink, green, magenta, white, tank or brown tips.

Even though this anemone is readily available, it has a poor record in captivity. Caring for the Delicate Sea Anemone can be tricky. It is reported to be easy by some aquarists and yet very difficult by others. As we come to understand anemones and their different needs, their quality of life increases. Just like fish, each species has its own quirks and needs.

This is a lagoon anemone with a sand fetish. It needs to have fine sand to burrow its foot into, yet also likes to be close to the surface. Unless it is happy, the Delicate Sea Anemone will roam the aquarium leaving a swath of destruction in its path. It will sting and consume corals and invertebrates, even fish. If it feels threatened, it will totally disappear into the sand. Provided with a thick bed of fine sand and good illumination, it will settle down and reward its owner with a long life.

For more information about Clown Fish anemones, see:
Facts About the 10 Clownfish Hosting Sea Anemones

Habitat: Distribution / Background

Sea Anemone Facts: The Delicate Sea Anemone Heteractis malu was described by Haddon and Shackleton in 1893. The Heteractis genus belongs to the Actiniidae family, and this genus contains 4 species. Some names they are known for are White Sand Anemone, Sebae Anemone, and Hawaiian Anemone. This anemone is not on the IUCN Red List for endangered species.

Where are Sea Anemones Found: The Heteractis malu is found in the Eastern Pacific Ocean and near the Hawaiian Islands.

Sea Anemone Habitat: Sebae Anemones are in sandy and gravel (round, smooth, small, gravel) areas at water depths of 7 to 66 feet (2-20 m). The only clown fish to host this anemone is the Clark’s Clownfish A. clarkii and possibly the False Percula or Ocellaris Clownfish A. ocellaris. They use their venomous cells or nematocysts found in their tentacles to sting and deflect any possible threats or attacks, and also use them to catch prey. Some predators can be other anemones, nudibranchs, sea stars and some angelfish. Bristle worms have been known to irritate and chew at Heteractis Anemones.

• Scientific Name: Heteractis malu
• IUCN Red List: NE – Not Evaluated or not listed

Description

Appearance of a Sea Anemone: The Delicate Sea Anemone or White Sand Anemone Heteractis malu has a sticky foot at the base of its pedal column used to adhere to various surfaces. They also use the “foot” to move around if conditions are not ideal. The color can be white with purple tips, pink, green, magenta, white, tank or brown.

The tentacles are variable in color and size, not reaching more than 4 cm, and are all over the surface of the oral disc. They are short and stocky with the center ones seemingly shorter than the outer ones. Close to the mouth they are usually a green-brown and then get lighter towards the peripheral.

The mouth is in the center of the oral disc. It should be closed and tight, and will open when hungry, having an oval look. A gaping mouth is a warning signal. The H. malu take food in and expel waste through this same opening.

Sea Anemones Life Cycles: The Delicate Sea Anemone is a runt in its genus, yet still reaches up to 8 inches (20 cm) in diameter. It is unknown how long they live, though in captivity they do not live as long as other anemones will. Some anemones can be hundreds of years old in the wild, and in captivity some have been known to last 80 years or more.

• Size of organism – inches: 8.0 inches (20.32 cm) – It reaches 8″ in diameter with it’s tentacles only reaching 4 cm in length.
• Lifespan: – Their lifespan is unknown, however they do not live as long as other anemones in captivity.

Difficulty of Care

Sea Anemone Care: The Delicate Sea Anemone has a poor record in captivity, and caring for it can be tricky. It is reported to be easy by some and yet very difficult by others. It is relatively hardy when provided the right environment. Supposedly the Hawaiian varieties are stronger. If this anemone is not happy, it will move around in the aquarium, leaving a swath of destruction in its path. Putting an anemone in a new tank can result in failure. The tank should be at least 8 to 12 months old and stable before adding your new H. malu.

The Delicate Sea Anemones have high lighting needs and must have a thick fine sand bed to bury their foot in. If this anemone feels threatened, it will totally disappear into the sand. One trick is a deep bowl filled with sand and situated near the top of the tank. There are imaginative ways to disguise the bowl. They need appropriate water movement and regular feeding. In fact, a lack of feeding is thought to be a further reason for their demise in captivity.

When choosing your anemone, make sure the color is good, their mouth is not gaping open, and their foot and tentacles are sticky to the touch. Also, 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 take an H. malu anemone from another aquarium, use a hair dryer. Blow at the foot of the anemone from the outside of the tank and the heat will make it pull away. If it’s attached to a rock, ideally you can simply purchase the rock as well. If you cannot purchase the rock then use ice cubes in a zip lock bag, and gently rub the foot all around until it releases. This may take a few minutes, but it is the most reliable way of getting your anemone to release. Don’t allow the fresh water of the ice cubes to touch the foot directly as this can cause tissue damage. H. malu can perish from any type of tissue damage.

• Aquarium Hardiness: Difficult
• Aquarist Experience Level: Advanced

Foods and Feeding

What Do Sea Anemones Eat: The Delicate Sea Anemone is a carnivore. In the wild, these anemones are well equipped with nutritional alternatives for their well-being. They derive daily nutrition from their symbiotic algae, zooxanthellae, that dwells within their tissues. They also use their venomous cells or nematocysts found in their tentacles to sting and capture prey. They absorb nutrients the water around them and they consume wastes from resident animals like clown fish. It is not necessary for them to be fed by Clownfish they host, though clowns will often carry chunks of food to the anemone.

In captivity you can feed your H. malu a mix of chopped fresh shrimp, fish and mussels from your grocery store. This variety is very good for these anemones, as they seem to derive their different dietary needs from these meats. Large anemones need food daily, medium sized anemones need to be fed 5 times a week, and the young or smaller ones need to be fed 2 to 4 times a week. The old adage that anemones should be fed once a month is false and has lead to many deaths.

Clownfish hosted with your anemone usually will not be able to sufficiently feed themselves and their anemone with the small quantity of food that is put in a captive environment. You will need to target feed this anemone. You can just offer your clowns a piece of fish flesh and they will usually snatch it out of your hand and give it to their host. However, not all clowns are this smart, so don’t depend on the clown fish to feed the anemone.

• Diet Type: Carnivore
• Meaty Food: All of Diet – They can be fed chopped fresh shrimp, fish and mussel from your grocery store.
• Feeding Frequency: – Depending on the size, feed your anemone anywhere from 2 times a week to daily. Larger anemones should be fed more often.

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. Keeping salinity stable with a top off mechanism is highly suggested. Keeping alkalinity at the typically acceptable range of 3.5 meq/l for reef tanks is advisable. A good protein skimmer is a must.

A Delicate Sea Anemone 3″ to 4″ is equal to 2 or 3 fish as far as waste production is concerned. 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. Additions of Iodine and and trace elements are suggested. Control phosphates with products such as Phosban and the Phosban reactor.

• Water Changes: Bi-weekly
• Alkalinity Levels: – Keeping alkalinity at the typically acceptable range of 3.5 meq/l for reef tanks is advisable.
• Iodine Levels: – Additions of Iodine and and trace elements are suggested.

Aquarium Setup

The typical live rock/reef environment is what is needed for your H. malu, with a deep fine sand substrate for it to settle into. Have at least an 8″ sand bed for them to bury their foot into. The Delicate Sea Anemone will attach to a hard surface through the sand. Once it is secured it, if it is happy it will stay put. If it isn’t happy and is moving around, be sure to check your lighting and water quality, also make sure you are feeding it adequately. With all anemones its 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: Sand
• Lighting Needs: High – Strong lighting
• Temperature: 74.0 to 83.0° F (23.3 to 28.3&deg C)
• Specific gravity: 1.023-1.025 SG
• Water Movement: Moderate
• Water Region: Top

Social Behaviors

All anemones are semi-aggressive because they can be mobile. The Delicate Sea Anemone tends to wander a little more than the other Heteractis, but that could be attributed to them not finding a nice sandy, high spot to settle into. Keep this in mind when stocking other corals. A contented anemone will stay put once it has found a place to settle.

It has often been suggested to not put anemones in a reef environment because corals cannot move away from the stinging tentacles. Once you have your anemone situated and it has not moved for several months, it might be safe to add other corals. Some predators can be other anemones, nudibranchs, sea stars and some angelfish. Bristle worms have been known to irritate and chew at Heteractis Anemones.

With the Delicate Sea Anemone, it is generally recommended that you don’t put any other anemones in the same tank. 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. However, after splitting, anemones will tolerate their own “clones”, and sometimes their own species. 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.”

If you want to have your anemone host a clownfish, be sure your anemone is 3 to 4 times larger in diameter than the length of the clown fish you introduce. It is best to buy the anemone first and give it a few months to acclimate and grow before adding clowns. Not all clowns take to all H. malu. Most species of adult clownfish tend to shun it. However It will provide shelter to various juvenile clownfish passing through on their journey to find a more suitable host anemone for adulthood.

In nature it has been found hosting the following clownfish:

• Clark’s Clown fish Amphiprion clarkii

Additionally, in captivity it has been known to also host the following:

• Maroon Clownfish Premnas biaculeatus

• Venomous: Yes
• Temperament: Semi-aggressive
• Compatible with:
  • Same species – conspecifics: Sometimes
  • Anemones: Threat
  • Mushroom Anemones – Corallimorphs: Threat
  • Leather Corals: Threat
  • Zoanthids – Button Polyps, Sea Mats: Threat
  • Sponges, Tunicates: Threat
  • Shrimps, Crabs, Snails: Monitor
  • Starfish: Threat
  • Feather Dusters, Bristle Worms, Flatworms: Threat
  • Clams, Scallops, Oysters: Monitor
  • Crabs: Monitor
  • Snails: Monitor
  • 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 H. malu typically do not breed 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: Difficult

Ailments / Diseases

Problems for the Delicate Sea Anemone are pretty minimal unless your lighting, water movement, feeding, and water quality are low. Then your anemone will detach to look for “better conditions.” In general, if your anemone moves, it is not happy. Some predators can be other anemones, nudibranchs, sea stars and some angelfish. Bristle worms also have been known to irritate and chew at H. malu.

Availability

The Delicate Sea Anemone or White Sand Anemone H. malu is easy to find in stores and online. The cost online starts at about $18.00 USD and goes up depending on size, color and species.

References

• Animal-World References: Marine and Reef
• Ronald L. Shimek, Guide to Marine Invertebrates: 500+ Essential-to-Know Aquarium Species, Microcosm, 2005
• Alf Jacob Nilsen and Svein A. Fossa, Reef Secrets: Starting Right, Selecting Fishes & Invertebrates, Advanced Biotope Techniques, T.F.H Publications inc., 2003
• Helmut Debelius and Hans A. Baensch, Marine Atlas Volume 1 (Baensch Marine Atlas), Microcosm Ltd, 1997
• Joyce D. Wilkerson, Clownfishes, TFH Publications, 1997
• Albert J Thiel, Heteractis Type Anemones, NetPets.org, Copyright 1995-2008

Featured Image Credit:  Heteractis malu by Haplochromis, Wikimedia Commons CC SA 3.0 Unported, 2.5 Generic, 2.0 Generic, and 1.0 Generic