by Phil C. Henderson


Choosing Your Next Anemone

Many hobbyist's first attempt at keeping marine fish involves the keeping of clownfish. Most are colorful, they have an interesting swimming motion, they are inexpensive and they are relatively hardy. Soon after the purchase of their clownfish many of those same people decide that their clownfish need an anemone. This is where many aquarist meet with their first failure. They find that even given good water conditions and good lighting their anemone still dies six to eight months later for no apparent reason. If the anemone does live, they may find they have a healthy clownfish and a beautiful anemone and neither one will have anything to do with the other. In this article I hope to give you some information that will help you to avoid these problems.

This information was gathered from over 30 aquarists like yourselves (some of them relatively famous) who have responded to my questions via the Internet (a worldwide computer network which has bulletin board services where aquarium related questions can by posted and answered), every clownfish host anemone book or scientific article I could get my hands on (and there aren't very many on keeping anemones out there), and Aquarists in charge of the tropical tanks at several public aquariums. When discussing the anemones I will give the scientific name first and then as many common names as I can before the information. (please understand that until recently not even the scientific names had been standardized) I don't mean to imply that my information is highly scientific; 30 people is hardly a good sampling. Hopefully those of you reading this article will be inspired to send me your experiences even if to tell me that you have had the same experiences.

First let me offer you some general anemone keeping tips:


The degree to which you are successful in keeping anemones may depend a great deal on your ability to chose a healthy one from the dealers tank. This is easier said than done. Some things are pretty obvious. Anemones with open, loose mouths, deflated tentacles, or torn bases should be avoided. Other things may be less obvious. White transparent color in an otherwise healthy anemone may mean that it has expelled all its zooxanthellae and that it may be perfectly fine for up to 9 months before it gradually starts to waste away. Short stubby tentacles on an anemone that is supposed to have long thin tentacles, even though it looks healthy otherwise, may mean it has already started to decline. If the anemone is not attached to anything in the dealers tank, it may have difficulty attaching to something in your tank and probably won't survive long. Watch as the dealer removes your anemone from his tank. If the anemone doesn't contract a little or react in some way, it is not a robust anemone. Lastly, if the anemones is not at least a little sticky to the touch, it may have lost the ability to fire its stinging cells (nematocysts), which means it will be difficult, if not impossible, to feed.

One of the unfortunate things about many of the hard to keep anemones especially, is that they seem to have a very slow metabolism. They are very slow to let us know that they are unhappy and by the time we notice, they may already be too far gone to help them since they are slow to react to beneficial changes too.

Clownfish host anemones all need lots of light to do well. They obtain most their nutrition from a symbiotic algae (zooxanthellae) that lives inside their tissues. Lots of light means from 3 to 6 watts of bulb per gallon of a standard depth aquarium. That means you need at least 4 of the longest bulbs that you can fit over your tank, usually in a ratio of 50% actinic and 50% full spectrum bulbs.

Anemones prefer water free of organic wastes, which in most cases means you need to have an efficient protein skimmer. Maintaining the levels of trace elements in the water by performing regular water changes or the addition of commercially available supplements also seems to be important. Charles Delbeek mentioned that iron supplements could benefit the zooxanthellae in the anemones. I found that the addition of CombiSan (which contains iron) seemed to help my sebae anemone regain its color. Moderate current, in addition to clean water, helps exchange needed elements and rid the anemone of waste products. Some of the more delicate anemones seem to prefer higher temperatures in the range of 78-80 F and pH in a consistent range of 8.2-8.4.

Feeding your anemone

Feeding can range from 3 times a week to once every 2 weeks. Some aquarists have had success not directly feeding their anemones at all, although I suspect their anemones are capturing food that is meant for the fish. Food usually consists of a piece of raw shrimp about the size of the anemone's mouth. Lance fish, silversides, clams, scallops and other frozen marine organisms can also be used, but I find them more messy. A large bag of peeled and deveined shrimp can be obtained from one of the local discount supermarkets and may last many, many months and has the added advantage of being fit for human consumption.

Liquid foods and Target foods may actually be harmful to your anemones directly (several aquarists stated that their anemones started to die as soon as they began to use liquid target foods) and indirectly though degradation of your water quality.

The jury is still out on vitamins. I could not find any common thread in my data that would point towards them being helpful or harmful. My suggestion would be to use them sparingly, or not at all.

Easier to keep anemones

Stichodactyla haddoni, Saddle Carpet, saddleback anemone, Haddoni anemone
This anemone is often not distinguished from other carpets in the dealers tanks. The tentacles are short and knobby and usually densely packed. There is usually a reddish to pinkish ring around the mouth that isn't present on other carpets. Groups of tentacles on the same anemone may be of different colors forming a striped pattern on the anemone. If not striped they are usually a greyish-green, although bright greens, yellows and even blues are sometimes seen.

Good Points- This may be the easiest anemone to keep for long periods of time. Light suitable for soft corals and commonly kept hard corals is enough. I have had one growing slowly for over 7 years in the bottom of a 30 gal. tall aquarium with only 60 watts of fluorescent light. Reasonable nitrate levels for fish seem to be OK for this anemone. For its first 3 years my anemone lived in water that measured 30 ppm of nitrate on a Seatest Kit and showed no ill effects. They will grow faster however given better conditions.

Bad Points- This anemone will eat your fish! (not your clownfish) Dwarf angels, small tangs, blennies and small shrimp seem to be prone to getting eaten. Pseudochromis, hawkfish and some others don't seem to have a problem. The clownfish that accept this anemone also seem to be limited. They are accepted by saddleback clowns, true sebae clowns, Clarki clowns and usually tomato clowns.

Entacmaea quadricolor, Bulb, bubble, bubble-tipped, maroon anemone
Recently obtained individuals will usually have unmistakable swollen ends on the tips of their tentacles. Specimens in captivity will often lose their bubble-tips for periods of time and just have long straight tentacles. The tentacles usually have a green color especially when exposed to only actinic light. The tentacles may also have a frosty white ring around the tip. The base is often rusty-red but may also be purple or just tan. The Rose anemone is a color variation of this anemone.

Good Points- Normal reef lighting is enough (above 4 watts per gal.) for this type of anemone and may be more than enough. Nitrate levels below 20 ppm are preferred. Small ones may reproduce asexually in your aquarium by dividing into two smaller anemones. Their sting is rather weak and won't harm your other fish. They are accepted by Clarki-type clowns, all the different tomato-type clowns, maroon clowns and sometimes, although very rarely, percula and ocellaris clowns.

Bad Points- These anemones tend to wander around the tank more than others, sometimes causing their own deaths from lack of light or being sucked through a powerhead. They like to have their foot shaded inside a crevice in the rock or coral with their tentacles in the light. This preference might be met by placing a short piece of PVC pipe, sized to the anemone, where you want the anemone to stay and putting its base into the pipe. They seem to be sensitive to being shipped. Make sure the one you pick out has a tight mouth and is firmly attached to something in the dealers tank. Any anemone that is not attached to something in the dealers tank is probably not healthy. In addition, when the dealer tries to remove the anemone from the tank the anemone should show some type of reaction, usually they contract.

Macrodactyla doreensis, Long-tentacled anemone
These anemones have very long (up to 5-6 in.), smooth, thick tentacles sometimes with longitudinal stripes extending into the oral disk. The tentacles originate from a round flat oral disk, distinguishing it from the condylactis anemone. The foot of the base is almost always bright red or orange.

Good Points- They are hardy if kept under Metal Halide lights. Under lower light levels they seem to slowly waste away. They come in a variety of patterns and colors including purple. Accepted by Clarki clowns, tomato-type clowns and pink skunk clowns.

Bad Points- They must have bright lighting. They normally live with their base buried deep in the sand and sometimes have a difficult time finding an attachment spot in a reef-type tank.

Difficult to keep anemones

Heteractis crispa or H. malu, Sebae anemone, Singapore anemone, pink-tipped (but not condylactis) anemone
Tentacles range from long and thin to short and fat depending on the condition of the anemone (short and fat usually means it is starting to waste away). Tentacles usually have magenta colored tips although yellowish-green tips are not uncommon. Colors can be dyed yellow, dyed pink, natural pink/purple, natural yellow, tan, but by far the most common is pure white. The oral disk may also have a green sheen under actinic light.

Good Points-They are very common in stores and are usually the least expensive of the host anemones. They are accepted by virtually all clownfish whether they occur together in nature or not. Some not so white specimens can regenerate their symbiotic algae thus becoming a brown color. If you can obtain a tan specimen with long thin tentacles they should do well under conditions similar to that required for bulb anemones.

Bad Points- No one I have spoken with, not even the public aquariums, can keep the white or yellow ones alive for more than 6-8 months. Out of the over 20 responses I received regarding sebaes only 2 anemones had stayed alive for over one year. Both of the anemones were tan in color either when purchased or had turned tan shortly there after. One thought is that sebae anemones may expel their symbiotic algae shortly after capture and when it is completely gone it is not easily replaced. Frank Greco of the New York Aquarium says that he has been successful in getting otherwise healthy sebaes to "color up" by feeding once a week with fresh fish, clam, shrimp or gelatin. They also get live brine shrimp, adult and baby, and a yeast based diet of his own design. In addition to the frequent feedings the anemones are exposed to very bright light, three 400 watt metal halide bulbs over the six foot by six foot, four foot tall anemone tank. If the anemone is not able to replace its zooxanthellae it is doomed to a very slow starvation once in the tank. There are cream colored sebae anemones found in shallow water in the wild, but they are not the transparent white color found in the dealers tanks. These don't seem to be a good beginner's anemone despite articles I have read that say they are.

Heteractis magnifica, Ritteri, African, yellow-tipped anemone
This anemone is usually rather large. Their tentacles are long with very blunt tips that are lighter in color than the shafts. The base may be red or purple but brown is more common.

Good Points- They are relatively common in the market. They are accepted by almost every variety of clownfish.

Bad Points- They tend to move to the highest point in the tank, often up the sides of the glass very near the water return pipe. In nature they tend to be found at the highest parts of the reef exposed to strong light and currents. In the aquarium they will need very strong lighting (metal halide) and very strong alternating (wave) currents to do well. They also have a reputation for being able to catch and eat medium sized non-clownfish.

Stichodactyla gigantea, Giant carpet, colored carpet
These anemones have short pointed tentacles that seem to constantly vibrate. The tentacles are usually not very densely packed except near the edges of the disk. Specimens with blue, bright green, yellow, or white tipped tentacles can be found and at some times of the year are even common, but light brown is still the most common color. The oral disk often lies in a wave pattern if the anemone is on a flat surface.

Good Points-The colored ones are very pretty! A pink specimen is featured on the cover of Martin Moe's "Beginner to Breeder " book. They are accepted by most clownfish.

Bad Points- They can sting non-clownfish and may even eat other anemones. Giant carpets unlike their relative the saddle carpet seem to be very difficult to keep in captivity. The only report I had of a success died in a move after living for 10 years and the aquarist was unable to have any success with any giant carpets after that. It is possible that the first anemone may have been a saddle carpet rather than a giant carpet, but I haven't been able to find out for sure. One of the reasons for the difficulty in keeping the giant carpets may stem from the fact that most are collected from very shallow water, sometimes less than 3 feet deep. This leads me to believe that it may be difficult for the aquarist to give the anemone all the light that it is accustomed to in nature.

There are a couple other natural clownfish host anemones that will sometimes appear in your dealers tanks, but I wasn't able to gather enough information on them to include an accurate description. These are the Sand, corn or aurora anemone (Heteractis aurora) and the Mertin's carpet (S. mertinii).

Some clownfish will also accept non-natural hosts such as purple mat anemones, reef anemones, condylactis anemones, gonipora corals and other long tentacled corals. There have been reports, however, that clownfish that associate with condylactis anemones and corals may be more prone to skin infections than normal.


The more anemone keeping experiences we can share the better. The more we can communicate with each other the more success we will all have. After many failures with sebae anemones, I have used information gathered from other hobbyists to choose a sebae anemone with a green oral disk and tan tentacles that has grown from 6 inches to 12 inches in diameter in 7 months.

If you disagree with my findings I would really like to here from you. If my findings agree with your experiences, I need to support some of the opinions I have already formed. You can reach me by e-mail at


Allen, G. R. 1972. The Anemonefishes - Their Classification and Biology - 2nd Edition. T.F.H. Publications Inc. Neptune City, New Jersey. 352 pages.

Allen, G. R. and Fautin, D. G 1992. Field Guide to Anemonefishes and their Host Sea Anemones. Western Australian Museum. Perth, WA. 160 pages.

Friese, U. Erich. 1993. Sea Anemones as a Hobby. T.F.H. Publications Inc. Neptune City, New Jersey. 319 pages.

Moe, M. A. Jr., 1992. The Marine Aquarium Handbook- Beginner to Breeder- New Edition. Green Turtle Publications. Plantain, Florida. 318 pages.

Sprung, J. 1994. Reef Notes. Freshwater and Marine Aquarium Magazine. 17(8):22.


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Mark Rosenstein