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My recent experience with anemones, mostly Entacmaea quadricolor (bubble tip anemone or BTA), has been quite pleasurable but not after considerable frustration with anemones in general. While I'm not aware of any secret recipe, I'm happy to share some of my observations and the setup that works for me. With a little luck and care, BTAs can do very well in your tank.
Almost fifteen years ago, I tried a 45G acrylic, all in one aquarium with 4 40W bulbs, a built-in box filter and one of the old "air stone" protein skimmers. In that tank, I had trouble keeping all but the hardiest invertebrates and in my eagerness, I killed a few anemones. They would last 4-8 weeks, never attach to the substrate and eventually bleach and whither. Not much fun to watch that happen.
Currently, I am enjoying considerable success with a more elaborate setup. The system is 210G, 22" deep, 30" front to back and 72" long. There are two sea swirls on the returns, a wide surface skimmer intact (of some interest in anemone keeping as you'll see below). Substrate is crushed coral sand, not oolitic. There is a 50G sump and no refugium with a large Precision Marine skimmer and a PM calcium reactor plus heater and chiller on a controller. Lighting consists of 3 400W 10000K MH bulbs and 4 blue VHO bulbs.
I feed the tank once or twice a day, a mix of Mysis, frozen formula one & two and angel formula, flake formula one and Spirulina. The anemones get frozen formula one, chopped clam, scallops or shrimp every 7-14 days in quarter inch chunks.
Lighting is 13 hours for the VHO and 8 hours for the MH. Tank parameters are 8.2pH, 13-15dkH alkalinity, calcium 300-350ppm, 77F ammonia, nitrites and nitrates are zero (even without a DSB). I dose with Lugol's once per week.
The fish load is on the light side but by no means non-existent.
With this setup, my Heteractis crispa seems very happy, having doubled in size and general staying put. My bubble tips have split, a green splitting once and a brown splitting 3 times. I had a maroon pair that used the BTAs but not the H. crispa. These were returned recently given their reputation of becoming terrors as they get older and I will replace with A. ocellaris, which will probably prefer the H. crispa. I've had the anemones from over a year to two years depending on the individual.
Here's some of the things I've learned about keeping these wonderful creatures.
Feeding and Starvation
Some otherwise good texts tell you that you need not feed a BTA that is hosting clowns. That is not my experience. A few years ago I tried this. It is not that the maroons would not bring the anemone food: they did from time to time. But it did not appear to be enough to sustain the anemone. It began shrinking after 12-16 weeks. Once the starvation set-in I could not get it to respond to food. It lasted for six months as a weird looking quarter-sized polyp but eventually disappeared.
Currently I feed every 7-14 days. The anemones seem to grow slowly at the 14 day end and quickly at 7 days. If you are trying to get your BTAs to split, I suggest feeding on the 7 day schedule. As neat as watching you BTA is, unless you are trying to split them for money, they will start taking up room and you may want to scale back especially if you do not have a bommie (see below) or an anemone only tank.
A healthy anemone seems to be a voracious eater, accepting chopped shrimp, clams or scallops as well as thawed formula one. As with most saltwater critters, a varied diet seems to help, most likely because they get a broader range of nutrients from a mix of food.
As long as the food is about quarter inch chunk or smaller, they seem to completely digest the food with little leftover that I've ever observed. The H. crispa does not deflate after feedings but the BTAs often deflate for several days while they digest. This seems perfectly normal.
Anemones do not engulf food quickly and other hungry things, namely cleaner shrimp, brittle stars and some fish like wrasses will poach the food. I found that feeding the fish normally and giving the shrimp and stars small chunks of their own food nearly eliminates the poaching. The principle here is to keep the poachers occupied while the anemones swallow.
I have not had this experience myself but I have read that hungry shrimp can tear an anemone. Certainly the shrimp and others are capable of stealing food. A clown may help protect the anemone during feeding although there are reports of the clowns poaching, too. In such a case, it is best to feed the clown 30 minutes before feeding the anemone. My maroons never poached but I've seen web accounts of tomato clowns and others poaching.
Best to select anemones that have not been held by the dealer for long. As long as there is no tear in the anemone, fresh is better because they do not have time to slide into an irreversible decline or suffer under the typically inadequate lighting in a dealer tank. Both wild and tank raised seem to do fine.
Bleaching or a very small size is a sure sign of problems. Avoid these. BTAs need not display "bubbles" on their tips to be healthy but they tend to do this when disturbed so you are likely to see such bubbles in the holding tank.
The Eponymous Bubbles
The bubbles on the bubble tip anemones are quite attractive. Don't get too attached to that look. They seem to come and go with time. In my experience, most BTAs do not regularly display bubbles except perhaps when disturbed. Bubbles do not seem to be an indicator of health, reproduction or anything other then maybe rough handle (as during collection, shipping, etc.)
I've never kept the rose colored ones although I am looking for one. Allegedly these are good at splitting and the bright orange ones can fetch $150 retail. The orange ones appear to hold their color over time but the green ones tend to fade although they will retain some green tint. Some brown ones may show red and green highlights under strong blue light, which is subtle but quite pretty. Not sure about the softer rose colored ones but they probably fade as well.
Bright light is appreciated but strong light is not essential. My tank is certainly well lit (1700W for 210G). The H. crispa is perfectly happy parked under 8 inches of water directly under a MH bulb but the BTAs seem to prefer lower down in my tank on angled slopes. Even the H. crispa has been happy at times in much dimmer locations. I take this to mean that in less well-lit tanks, they will simply move higher to get equivalent light but that the full light of my setup is not required.
I saw H. malu in the south pacific mostly under ledges and seemingly doing quite well. In short, good spectrum and moderately bright light should be fine. Very high-end lighting is probably not required but I haven't experimented myself. Of course, if you have it or can afford it, very strong lighting is better since the anemone can always scoot over to some dimmer location in a bright tank but it cannot to the reverse in a dim tank.
I have noticed no particular preference for current strength. Mild to strong all seem to work. Mine sometimes end up in completely dead spots and seem happy.
Healthy BTAs sting corals. Don't let anyone tell you that theirs don't bother anything. Some things tolerate the stinging well, others don't. In my experience, Hydnophora, Zoanthids, Montipora, and H. crispa will close or pull back but seem to suffer no lasting damage. My orange Montipora digitata will actually bleach if in contact for more than an hour but the color seems to come back within two days. My Porites has been severely damaged by BTA stings. See my suggestion for a bommie below for how to mix corals and anemones in the same tank.
On the fish front, I have never observed any harm to my fish but I suspect that a mandarin pair was stung by my BTAs and will not try these in this tank again (better in a quiet tank anyway). Both died a horrible twitching death in front of my wife, which was not a good thing since she was rather attached to them. There have been a small number of fish disappearances over the years that could be anemone related but I think it unlikely.
Overall, any reasonable swimmer seems to do fine with BTAs but you do hear stories of fish being captured and the standard advice is not to keep anemones with anything you can't bear to lose. Jawfish (which I don't keep) are reputed to be particularly prone to death by anemone.
The LR arrangement is actually of some importance for BTAs. The books tell you they like crevices in which to hide their bases and they are 100% correct. Ledge arrangements, which the fish love, are tolerated by BTAs but I find that BTAs rarely wander much when they have good crevices but sooner or later wander if they only have ledges to choose from.
I base this observation on my old rock arrangement that tended to ledges on one side of the tank and the other side more crevice ridden. On the ledge side, the anemones would wander long distance every 2-4 months. On the crevice side, they would not wander far. I suspect this is because with many crevices, they can soon find an attractive spot not far from where they started but with ledges, they have to move considerable distances for a change and once they get moving they can move fairly far.
One thing to watch out for are "anemone traps" in your rockwork. These tend to be caves and arcs near the sand where the anemones tend to end up and but are not well suited for them. These formations seem to be easy for the anemone to get into but hard to get out of. They are hard to predict ahead of time but over time, if you see your anemones ending up in these frequently but not attaching, consider rearranging the rockwork to eliminate the trap.
Powerheads are the bane of anemones. There are lots of pictures on the web and in books of anemones mangled by intakes. They may either crawl into the intake or when they are really in a wandering mood, they tend to drift in the current and naturally get sucked into a high current area.
If you keep anemones, you should either not have any powerheads in the tank or make sure that the powerhead intake is diffused by a large sponge. Otherwise, you will sooner or later get one sucked into a powerhead. This is almost always fatal for the anemone.
Overflow intakes can also pose a problem but these tend to be larger and therefore the flow at any one point is lower and less of a problem. I only once had an anemone at my intake and caught him early enough that he did not get sucked into it so no harm done.
If you keep BTAs, you will eventually recognize when one of them has wanderlust. When they seem to be on the move, best to keep an eye on them in case they get near an intake. The one that hit my intake had had the wanderlust in him for several days and fortunately I checked the tank before bed one night, specifically checking on him, and caught him at the intake. I put him in the crevice side of the tank and he stayed put after that.
Some amount of wandering, especially after splitting, seems normal. But if your anemone wanders constantly or doesn't attach, this is a sign of an unhappy anemone looking for a better home.
The things to try are: rearrange the rockwork to provide more crevices and a perch closer to the light; stronger lighting; more frequent feeding.
If the anemone will not settle down, it is a sure sign that it is not going to thrive. If you can't get it to settle, you may want to find it a new home before it goes into irreversible decline.
Be aware that in addition to anemones "walking" on their foot, they can also balloon up and drift around. When drifting they can end up anywhere in your tank very quickly, including on that prize coral of yours or the intake. In my experience, with lots of crevices, good food and decent lighting, they will not drift and instead just wander about on foot a bit.
To minimize wander, minimize the risk of the anemone ending up in an intake and to segregate from your corals, consider building a little anemone "bommie." This is a freestanding pile of rock that favors crevices. If you like, you can put caves for fish at the very bottom but construct the rest of the rock mound so that is more brick-wall like than generally recommended so that there are lots of small crevices for the anemones to hide their bases.
Unless they are terribly unhappy and are deciding to drift with the current, the BTAs will stay on the bommie. I've never seen one crawling on sand or gravel, probably because they can't get a grip. The bommie arrangement serves as an attractive site to them, thanks to the crevices with the sand providing a "moat" to keep the anemones away from the rest of your LR with your corals or from the tank walls where they can get into an intake.
Your bommie can have some hardier corals on it but in time, it will fill with anemone clones. With a mix of color morphs, this can be quite spectacular. My bommie has some encrusting gorgonians, some mushrooms, and some zoanthids plus some Montipora which seems reasonably sting tolerant (and grows so fast anyway that one dead sprig isn't heartbreaking.)
When selecting a tank specifically with anemones in mind, consider one that is 30 inches front to back. This will give you plenty of room for a nice bommie that stands away from any wall. Remember the bommie must be free standing. It defeats the purpose to have it touching the rest of your rock or a wall.
If you have MH bulbs consider positioning the bommie under one. You may find that your BTAs tend to stick to the bommie sides but with an MH bulb directly overhead, all sides will be very well lit and suitable for the anemones.
The bommie isn't a cure-all. Anemones will occasionally float in the current and therefore could leave the bommie but it is a help and hopefully you can catch it while floating and put it back on the bommie.
My own bommie is relatively recent. Before that I had a standard "back wall of rock."
Clowns are good. In the wild, few anemones survive without clowns. In your tank, this seems less important but if it works in the wild, it can't hurt in the tank. When selecting clowns, it is best to try to get a clown-anemone pair that is found in the wild although many clowns will accept nearly any host. Some clowns can get quite aggressive so do your research.
Some tank raised ocellaris sometimes are slow to accept an anemone. Here's an amusing but effective trick: buy one of those plastic clownfish clips used for holding Nori or lettuce and put it right by the anemone. Believe it or not, the clowns will think it is a fellow clownfish and swim to it. They may then take to the anemone. Strange as this sounds, I do not kid you. You could also try putting a picture of a clown in your tank but I'd be nervous about inks or dyes leaching into the water unless you seal or bag it very well.
Don't have too much to offer on splitting except that a well fed BTA seems to split sooner or later. Splitting seems to come in batches. A BTA may get very large then suddenly split several times. As with most asexual reproduction of Cnidarians, feeding aggressively seems to encourage splitting. This isn't necessarily a good thing if you don't have a tank with lots of room for things that move a lot and pack a good sting.
If you have the more attractive color morphs you can get a steady cash supplement selling the clones.
I am by no means an expert aquarist. I have only successfully kept anemones for a few years and even then, not large numbers of them. But I do try to observe carefully and it is these observations (and some conclusions) that I have shared in hopes that you will have success with your anemones.