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Related FAQs: Magnificent Anemones, Magnificent Anemone Identification, Magnificent Anemone Behavior, Magnificent Anemone Compatibility, Magnificent Anemone Selection, Magnificent Anemone Systems, Magnificent Anemone Feeding,
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/Diversity of Aquatic Life Series

Heteractis magnifica; Magnificent Anemones. A Poor Choice for Most Captive Systems

By Bob Fenner

Off Queensland, Australia

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Anemone Success
Doing what it takes to keep Anemones healthy long-term

by Robert (Bob) Fenner

Amongst the several large Pacific Anemones naturally symbiotic with the playful Clownfishes (subfamily Amphiprionae), the Magnificent (Heteractis magnifica) ranks near the bottom for inappropriate aquarium use. This is a naturally large (only second to Stichodactyla mertensii in potential size for symbiotic anemones), species that is given to frequent moving... even "ballooning", filling itself with water and floating off to have adventures... Too big and free-roaming for anything but huge hobbyist systems (hundreds to thousands of gallons) with little other stinging-celled life. Want more? Of Anemones the Magnificent requires about the most intense lighting and water movement... and let's top it off with this species propensity to eat your non-hosted aquarium fishes!

Nonetheless, this species does make it into aquarium markets and aquarists tanks... Here is my best shot at informing you what it takes to successfully (as in potentially forever) keep this magnificent animal in captivity.


Heteractis magnifica (Quoy & Gaimard 1833), the Magnificent Anemone. To thirty some inches across (a meter). Tentacles and oral disc of the same color, with a base/pedicle also colored... Typically purplish, but may be red, white/tan, brown, green or blue. Previously and in older literature often labeled as Radianthus ritteri (Hence this species is also often referred to as Ritter's or the Ritteri Anemone). Found widely in the Indo-Mid Pacific; East Africa and the Red Sea to Australia, S. Japan, to the Tuamotu Archipelago (French Polynesia).

Joy in Australia for Percula Clowns

Diana's close-up pix of pedicle/base showing prominent verrucae (warty textured striations) and tentacles with distinctive longish, blunt ends. In the Red Sea.

Typical postures of Heteractis magnifica, showing a range of base colors. Aquarium image at right, Three showing different pedicle color in Pulau Redang, Malaysia below.

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This species does/will move quite a bit... unfortunately. Likely their easy and eager motility is linked to finding more favorable conditions, but this condition merits reminding! Do be cautioned that your Magnificent Anemone will likely move about... They can/do stay for a while in areas of good lighting and water movement... but, as the saying goes "The grass is always greener" or in this case, "The current is always stronger"... on the other side... and H. magnifica is determined to find it. Hopefully your intakes/overflows are well-screened and redundant, and/or you'll be about when yours takes a journey... Anemones go where they are most comfortable. I recommend leaving them alone.

Changing color. They do... Depending on local conditions yours may well change to something else... and back again... due to light, foods/feeding... water quality. If yours starts to do such changing, this should be a signal to you that something is going on in/with your system... Are you lighting lamps getting old? Is there summat amiss with your water quality? Or, has a change in your foods/feeding protocol brought this about?

A natural behavior I'd like to relate is the sometimes clustering of individuals in the wild. W. Indonesia and Malaysia (Palau Redang), I've seen groupings (hundreds of individuals... at one place about a city block) side by side, occupied by several species of Clownfishes... apparently cooperating in protecting this massive Clown Condo project... swimming out to greet us divers, and woe the seeming predator of "their" Anemone field.

At right, a scene of "hippy" Clowns in Palau Redang, Malaysia... Are these Anemones all clones?


At least twelve Clownfishes naturally form symbiotic relations with the Magnificent Anemone; the rest may or may not in captive circumstances. The best means of introducing parties is to place the anemone first, allow it a few weeks to settle in... Then the clowns, ideally as immature individuals... If you have tank-bred stock or otherwise "clue-less" Clowns that don't either seem to recognize the hosting anemone for what it is, one trick that has proven useful is to place a plastic "Clown shaped" (yes, even though it doesn't move... and it's green in color!) in the tank, stuck with its suction cup on the glass... near the anemone. Often this "sham" competitor is all it takes to nudge the "free agents" to partnering up.

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Here a H. magnifica stinging an Acroporid in the Red Sea.

Also, it may help to place new livestock either early in the morning, or to leave the lights on the tank or one near the tank on overnight the first night or two. Know that ritteri (Heteractis magnifica) will eat most any fish, invertebrate that happens into its tentacles, and that they can/do expand quite a bit at times...

Clownfish/Damsel Species Naturally Symbiotic with Magnificent Anemones
A. akallopisos Skunk Anemonefish
A. akindynos Barrier Reef Anemonefish
A. bicinctus Two-Stripe Clown
A. chrysogaster Mauritian Anemonefish
A. chrysopterus Orange-Fin Anemonefish
A. clarkii Clark's Clown
A. leucokranos White-Bonnet Anemonefish
A. melanopus Red & Black Anemonefish
A. nigripes Maldives Anemonefish
A. ocellaris False Clown Anemonefish
A. percula Clown Anemonefish
A. perideraion Pink Anemonefish
A. xanthurus Yellowtail clownfish
Dascyllus trimaculatus Domino Damsel

If you can, please do resist mixing corals and other stinging-celled and anemones... motile cnidarians mixed with sessile ones are a recipe for disaster in the long run. This being stated, given enough room, starting with small colonies, good placement of rock, perches... all this mis-mix can/will "growing up together" learn to get along, tolerate each other... Always remember though, there is a distinct possibility that the Heteractis magnifica will detach at some point... real trouble not if, when it contacts other cnidarians... hopefully someone will catch this quickly... Remember this pre-admonition


Not generally delicate, a healthy specimen of H. magnifica is not hard to spot... It certainly won't be open to the size it was/is in the wild at your dealers... but do look to the foot of the animal first and foremost. It should not have obvious tears on the pedal disc, nor "cut in" areas portending this tearing on the pedicle on down to the disc.

Avoid Bleached Specimens:

There are no naturally white-colored Magnificent Anemones... and it's rare for ones that are badly bleached to recover...

Down in the Mouth:

Amongst the large commensal anemone species, the Magnificent is the only one that often has an obvious open mouth when healthy. If a prospective purpose appears sound otherwise, don't let "loose lips" defer your purchase.


First of all, space... lots of room... big volumes... You may be saying to yourself... "Gee, the specimen I'm interested in only looks like it's about the size of my hand"... I assure you this animal is much, MUCH larger... I have never seen such small individuals out diving... The collected ones are squeezed (yes) to make them smaller for shipping... The can/do expand with health, growth, happiness... You need hundreds of gallons to keep this animal long term. Also, new tanks need not apply. Your tank needs to be well established to keep this anemone, six months minimum, a year preferable.

Where do they live? In the wild in exposed areas, attached to rock... where there is sufficient current or surge, in five to twenty meters of depth. You may have to situate yours on top of a large bommie-like arrangement of rock to elevate it close enough to what lighting you can provide... Likely no more than a foot underwater... Place the animal about halfway on this structure and let it decide... It will.

A picture is worth a whole bunch of words as the saying goes. Here's a ginormous Magnificent Anemone off Egypt's Sinai at "Anemone City" (Ras Mohamed)... This is a single individual wrapped around the upper area of coral rock... with a BUNCH of Three Spot Damsels and a mix of Bicinctus Clowns it's hosting.

Bright light, big city... this anemone can and will survive under this lighting if it climbs and stays in the top half of the aquarium. To be sure you are getting the best light output from your fixture, do be sure not to use a glass canopy. These block out light. If you are concerned about fish jumping, please find and use some eggcrate. This is what we in the US hobby calls what other industries term "louver". It is found at most any hardware store, mainly in 2 by four foot panels; it's real purpose is diffusing light on overhead fluorescent fixtures. Your specimen might easily be photo-shocked by being exposed to too much light too soon, after being kept "in the dark" during holding, transport. You might initially place a stack of plastic fiberglass fly screen (like for windows) on top of the canopy between the lights and the water. About 12-15 sheets should do nicely. Remove a sheet every day or every other day for a few days to gradually acclimate the anemone to the new light over a couple of weeks. Oh, and what sort of light fixturing? A bunch of boosted fluorescent technology might get you by with enhanced ancillary feeding, but in practical terms either 250 or 400w MHs of the 6500k or 10000k color spectrum (along with some natural sunlight if possible) are best.

Some water movement now! Magnificents' also need flow in the thousands of gallons per hour (no laminar streams either)... we're talking good-sized submersible pumps like Tunzes, Hydors galore on a wave making device to time their action, and/or a good arrangement of dedicated plumbing and pump for closed-loop circulation.

Ideal system is very centered around this species, its host fishes (likely one species of clown and the Domino Dascyllus)... placing the anemone on a high apex of carefully stacked rock to about a foot underwater, under one, two or more Metal Halide lights (of... about 10k K temp.), with circulation arranged either statically or through a wave making/surge device... moving the water in a BRISK fashion at any length... and precious little else population-wise, unless the system is HUGE.


All host anemones need to be fed. If yours is shrinking, I would suggest increasing the feedings. Don't worry, the anemone will reject food if it is being overfed. Foods of not too large a size (Portions should be smaller than its mouth. Gently drop the food near its mouth. If it is regurgitating the food, try an even smaller piece.), such as krill, squid, silversides, lancefish, Mysis shrimp, Pacifica plankton, shredded raw food shrimp, minced krill etc. about 3x weekly along with photosynthesis should provide adequate nutrition.

Soaking foods in vitamin & HUFA prep.s (e.g. Selcon). and supplement with Iodine/ide is a good practice once a week.

You may find that your Clowns, rather than occasionally feeding their host anemone, are cagily involved in stealing its foods. Why do these fishes keep taking the pieces of food you place in your anemone out of it? Simple - they want the food! A good technique here is to purposely feed the Clowns first... then 10-15 minutes later the anemone.


The present state of our, well at least my, understanding of Actinarian health is rather primitive... Suffice it to state that most all anemones appear fine, do well... until, given obvious to obscure reasons they're just about to actually dead. The onus is upon you to carefully monitor the operation of all gear, be diligent re water quality testing, keep up with your maintenance regime... AND carefully observe your specimen. The value of quick assessment and possible large successive water changes cannot be overstated. Likely you will NOT have another system to move your specimen/s to... So... the REGULAR change-outs of water, use of chemical filtrants like good quality activated carbon, ozone... are requisite in keeping anemones... Particularly ones of size such as H. magnifica.


Dr. Ron Shimek wrote a small pamphlet called "Host Anemone Secrets." it is really pretty good and he has good experience with H. magnifica getting his to spawn. This does occur "naturally" due to propitious or demanding circumstances... and can be induced by careful cutting through the mouth and body.


So, do you have an established system of a few to several hundred plus gallons (three feet across in all dimensions minimum), with plenty, and I mean PLENTY of lighting and water movement? The patience, nerve to risk this Anemone coming loose, moving about, stinging your other "Corals" (and other Cnidarian life), as well as possibly your fishes? Maybe another Actinarian species is a better match... My best advice, request is that you leave the Magnificent Anemones in the tropical seas where they belong.

Bibliography/Further Reading:



Fatherree, James. 2002. Keeping Sea Anemones. What you need to know. TFH 12/02

Fautin, Daphne G. & Gerald R. Allen. 1992, revised ed. 1997. Anemone Fishes and Their Host Sea Anemones. Western Australian Museum. 160 pp.

Fautin, Daphne G. 2006. Hexacorallians of the World. http://geoportal.kgs.ku.edu/hexacoral/anemone2/index.cfm

Fenner, Robert. 1992. Anemones in captive systems. FAMA 10/92

Karli, Scott W. 2003. Sea Anemones. FAMA 1/03.

Shimek, Ronald L. 2002. Host Anemones. Responsible care will ensure their survival. AFM 10/03

Shimek, Ronald L. 2003. Anemone troubleshooting; With no defined life span, anemones may last indefinitely- but only if given proper care by an aquarist who researches their needs and meets their care requirements. AFM 10/03

Shimek, Ronald L. 2004. Are any Anemones right for beginners? In a stable tank, a couple species might work. AFM 3/04

Toonen, Rob. 2001. Invert Insights (column) Re: Anemones, Clownfish symbionts. TFH 9/01.

Toonen, Rob. 2003. Ask the Reefer (column). Gen. disc. re Anemones in captivity. TFH 3/03.

A pic of one of a few specimens that appear bright red at depths of 60-90 feet, but not so with camera flash... in the Red Sea.

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