Bubble-Tip Anemone Safety Tips

Nippy tankmates are one reason a bubble-tip anemone may start to roam

Nippy tankmates are one reason a bubble-tip anemone may start to roam

The bubble-tip anemone (Entacmaea quadricolor), or BTA, is justifiably popular in the marine aquarium hobby, being relatively hardy and easy to keep as anemones go as well as being a suitable host anemone for many clownfish species. But to horribly misquote legendary singer Dion DiMucci, “it’s the type of nem that likes to roam around”—particularly when it’s getting settled into a new system or decides it’s unhappy with its placement in an established one.

The problem with an anemone going parading around its aquarium is that anytime it does so, it has the potential of blundering into equipment or other sessile invertebrates with potentially injurious (or even fatal) consequences. Thus, any system housing a BTA must be designed or modified to reduce the risk of accidental injury or harmful interspecific encounters.

Here are several important factors to consider when BTA-proofing your tank:

Crowded reef tanks aren’t ideal for BTAs

People do keep BTAs in reef systems among various corals and other sessile invertebrates. However, as alluded above, this can prove problematic if the anemone goes roaming, as it may sting or be stung by any inverts it encounters in its travels (though not all corals are equally sensitive to the sting of a BTA and vice versa). Not to mention, problems with allelopathy (chemical warfare) among inverts tend to be much greater in mixed reefs. The best housing for a BTA is a good-sized system dedicated specifically to its needs.

(If you’ve had long-term success keeping a BTA in a mixed reef, we’d love to hear how you managed it in the comment section below.)

Pumps and powerheads are problematic

bta-safety2Submersible pumps and powerheads are among the biggest offenders when it comes to injuring/killing wandering nems, so the intakes of these devices must be screened off with sponge, foam, or a similar material. The screening material must not only create a physical barrier, but also diffuse the suction so the anemone’s tentacles or foot can’t get trapped on the intake or actually get sucked inside the pump.

Keep in mind that the material protecting the intake will trap a lot of debris, so you’ll need to remove and rinse it frequently to prevent clogging and the subsequent reduction of water flow.

Heaters can be harmful

Aquarium heaters can also present a major health hazard to nems. To prevent a wandering BTA from contacting or attaching itself to a heater and being severely scalded, it’s best to place the heater down in a sump rather in the main display tank. If that’s not an option, the heater needs to be isolated in such a manner that the anemone can’t reach it, but the water can still easily flow around it—for example, by inserting the heater in a section of PVC pipe with holes drilled through it.

Stable, optimal conditions discourage roaming

Once a BTA settles into a suitable location in its new home (typically with its foot attached down inside a rocky crevice), it will be more inclined to remain in that location if conditions are kept stable and optimal. So be sure to guard against issues such as:

  • Fluctuations in temperature, pH, specific gravity, or other water parameters
  • Gradually deteriorating water quality
  • Gradually declining light intensity/shifting spectral characteristics (change bulbs/tubes on an appropriate schedule, clean cover glasses, etc.)
  • Corals encroaching on the anemone as their colonies increase in size or spread from rock to rock (another argument for giving anemones a dedicate tank)
  • Nippy fish tankmates

These and any other influences that impact the stability of the system or alter living conditions for the worse can prompt a BTA to detach and go roaming in search of “greener pastures,” potentially putting itself or tankmates at risk in the process.

Photo credit: Cathy Thomas, Great uncle


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. Well before the movie “Finding Nemo” came out I have always been a huge fan of the symbiotic relationship between the anemone and the clown fish. I have various experiences on all of the popular anemones from Bubble tips, Ritteri, Long Tentacles, Sebae , Carpets, maxi minis and even Tube anemones throughout the years till I ended up moving and decided to try my luck at SPS and LPS. The last batch of anemones I had were a cluster of Rose BTA and LTA that I had for over 8 years and at approximately 10-14″ diameter at their peak expansion in a 125 gallon mixed reef. The greatest lesson this past decade have been there’s never a true mixed reef that you can satisfy the requirements of everything easily so I ended up splitting things up by needs these days.
    The anemones did well with metal halide lighting, good non-laminar flow, and occasional feeding. Having a hosting clowns were a bonus but never necessary, If I would do it again I would have an anemone species tank with a harem of clowns. The simplicity of this system is still very enjoyable.

    • Jeff Kurtz says

      Sounds like you’ve had some really neat tanks, Ellery! I’d bet clownfish/anemone symbiosis has drawn more people into the hobby than just about any other influence. Thanks for sharing this!

  2. By BTA started shriveling up daily (for the past 3 days) at about 2pm then looked fine when the lights went off at about 5pm. Is this just a coincidence or is there something going on with my water parameters?

    • Jeff Kurtz says

      Hi Gmailer! It’s tough to pinpoint an exact cause for this behavior, as BTAs will shrivel like that for any number of reasons. Is it newly introduced, and does it look pretty healthy otherwise? If so, the behavior might just be attributable to its getting acclimated to new conditions. The fact that it seems to shrivel late in the photoperiod and then reinflate when the lights go off makes me suspect that it might be related to lighting, but that’s purely speculation. BTAs will also do this when expelling waste, so that’s another possibility to consider. Of course, it’s always a good idea to double check all your parameters to make sure they’re spot on. Keep a close eye on the specimen, and be sure to keep us posted!

  3. I just got a submersible pump for my salt water tank. Thanks for explaining that my pump can hurt my wandering nems! I’ll be sure to put a sponge over the intake pipe to prevent them from being sucked in.

  4. I have a green bra that came with a resident crab. It roamed for a day and finally tucked its foot inside a rock and has stayed there for a month now I read that I need to feed occasionally and did so wth a little krill. But noticed it had been spit out after a day or two. I feed the fish mysis shrimp will this suffice for the Bta and crab. They seem to be doing great since I tried to feed it krill over 2wks ago

  5. Sherwood Johnson says

    I don’t do my BTAs any favors. The occasional one gets pulled into a pump and shredded, and I do nothing to protect them against neighboring coral (although I did place a rock to protect a neighboring brain from the BTA … and the accompanying clowns now lay eggs every 2-3 weeks under the rock!).
    In fact, my main problem with BTAs in my reef tank is that they get huge, divide, and the offspring then travel in search of new homes. On rare occasion, I will catch one on the glass and scrape it off, and return it to my LFS but, generally speaking, they would multiply faster than I could get rid of them.
    In desperation, I purchased *serrated* scissors (regular scissors wont grab the tissue) chopped up the newer, smaller ones that split off, removing any larger pieces when possible and letting the smaller ones float off into the tank. I now do this weekly, as needed, so they essentially starve.
    It sounds horribly barbaric and nasty for a reef tank (think rotting, stinging tentacles everywhere), but it has worked very well to keep a balance between coral and anemones! It also allows you to select anemones that are well-behaved and get rid of meandering ones. (Note: I have always kept one “spare” small anemone in case the mother ship died … which hasn’t happened yet).

    • Jeff Kurtz says

      Sounds like you might be better served by a post entitled “Bubble-Tip Anemone Population Control.” He he! Thanks for sharing your experience with us, Sherwood!

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