By Steven Pro
There are various methods that
hobbyists have tried in an effort to rid themselves and their display of the
pest anemones Aiptasia
and Anemonia majano. Some have
attempted various methods of chemical warfare while others have employed
biological means to eradicate these pests and still others have attempted
physical removal. These techniques each have their various pros and cons; all of
these work sometimes, but they also fail sometimes, too. In that regard, I have
found a few ways that I prefer over others. Usually, the reason why I prefer one
method over another falls under one of several categories; the first reason
being that it seems to work more often. Another good reason to pick a method is
because it is easier to apply. And lastly, some of these techniques are less
risky than others.
Wanted... not "dead or alive," just
dead! Aiptasia sp. (top) and Anemonia cf. majano
The Bad Guys
Aiptasia, commonly referred to as
"Glass" or "Rock Anemones," are a frequently encountered pest anemone. They are
typically a translucent cream to brown color with tentacles that come to a
point. Often you will hear people describe them as having a "flower-like"
appearance. Even though that is a pretty good description, they are not a
delicate flower. They are much more similar to an invasive weed. Think of them
as the tough little Dandelion of the aquarium hobby. They are unattractive,
reproduce easily, have powerful stinging nematocysts which can harm or outright
kill the corals or clams in the tank, and they can be challenging to eradicate.
Aiptasia are native to the Caribbean, but are often introduced through
hitch-hiking on corals and rock that has been kept in systems where Aiptasia
have been introduced.
These are the prettier of the two
common pest anemones. I have seen specimens in green, red, and even a striking
yellow. They are somewhat less of a nuisance than Aiptasia, partially because
they are somewhat attractive, but primarily because they are not nearly as
prolific. They can be easily distinguished from Aiptasia because they have
bulbous tips on the ends of their tentacles. Unfortunately, like
Aiptasia, they have a potent sting and can become a danger to the other
sessile invertebrates in the aquarium. Anemonia are Indo-Pacific in origin.
Biological Means of Control
Berghia nudibranches attacking an
Aiptasia anemone. These beautiful creatures are easily cultured and are
an effective control for aiptasia, but since they easily fall victim to
predation, they work best when infested live rock can be removed from
the display for "cleaning." Photo by Anthony Calfo
These little nudibranches are
natural predators of the pest anemone
Aiptasia. In fact, that is all they ever eat, so they are a perfect choice
for ridding your tank of Aiptasia.
But, they do have some problems. Mainly, they are hard to find. Few local fish
stores carry them. I have mostly been able to find them at specialty online
vendors or in trade from other hobbyists. Secondly, they are expensive. The old
rule of supply versus demand keeps their price dear. Third, many people sell
them when they are too small and underdeveloped. This causes unnecessary losses
in transit. And lastly, you can’t just buy a couple, toss them into your
display, and expect them to find and eat all your
Aiptasia. It just doesn’t work that way. Most of the time, they just
disappear without doing anything if merely tossed into a reef tank. They likely
fall prey to fish or other invertebrates when used in this manner. The best way
to utilize these nudibranches is to keep them in a separate tank where they are
protected and transfer pieces of infested rock from the display into their
little world where they can clean it. Once a piece of live rock is free of
Aiptasia, it can be replaced in the main display and a new piece of rock can
be transferred for cleaning. This process is tedious, but it is hands down the
most effective method. As an added benefit, these nudibranches breed so readily
that you will soon be rewarded with eggs and offspring by keeping them in
isolation. Berghia are, in fact, quite
prolific. Even at the age of 7-8 weeks old, young adults are capable of
producing an egg ribbon every other day when well fed. The potential of turning
a couple of adults into hundreds to help you in your battle against
in just a few months is quite possible!
You may even be able to rid your tank of this pest anemone and make a few bucks
by selling your extra nudibranches!
Catalaphyllia jardinei, the
Elegance Coral, is capable of damaging pest anemones with its powerful
This method was originally reported
by Julian Sprung in his
Reef Notes column in Freshwater And Marine Aquarium (FAMA)
magazine. It was republished and repackaged in his little Reef Notes book
Volume 4. The source of the suggestion is attributed to John Brandt from
Chicago. You may have heard that name, since he is actively involved in the
Marine Aquarium Society of North America, MASNA, the people that sanction the
annual convention known as MACNA, the Marine Aquarium Conference of North
America. The idea is that the strong stinging nematocysts of the Elegance coral,
Catalaphyllia jardinei, could be used to kill the
Aiptasia. While this may possibly work, Elegance corals routinely suffer
upon import nowadays. It is frankly unusual to hear of someone being able to
keep one long-term lately. As such, if you were to find a healthy one, I would
not recommend risking it in a battle royal with
In all fairness to Mr. Sprung, he
originally suggested this method when Elegance corals were considered a hardy
coral. Back in the day, they were a good beginner’s coral. Now, most suffer and
die from unexplained causes. There is one ongoing study by Eric Borneman that is
looking into why they no longer seem to thrive in captivity, but regardless of
the outcome of this experiment, I doubt most people would be willing to
jeopardize their newest, pretty acquisition on an ugly pest anemone when other
means are readily available, less precarious, and certainly not as expensive.
Chelmon rostratus, the
Copperbanded Butterfly, is widely used to control Aiptasia sp.
The Pomacanthus imperator,
the Emperor Angelfish, will often prey on Anemonia sp. It can be
risky to house this fish with desirable anemones and corals.
There are numerous fish that are
sometimes mentioned to help control pest anemone problems. The Copperbanded
Butterflyfish, Chelmon rostrata, is
the mostly commonly recommended to prey upon Aiptasia. Some aquarists also advocate the Raccoon Butterflyfish, Chaetodon lunula, for controlling Aiptasia the Emperor Angelfish, Pomacanthus imperator, is sometimes utilized against
Anemonia majano. None of them is guaranteed to eat the target organism. But
even if they do eat them, more often than not, they also nip at some specimens
that the hobbyist doesn’t want them to attack. Copperbanded Butterflyfish are
generally safer than the other two, but they are known to also prey upon feather
dusters/tube worms and might sample the occasional large polyp stony coral, SPS,
soft coral, or clam. The Raccoon Butterflyfish is not considered to be
‘reef-safe’ and neither is the Emperor Angelfish. The Raccoon will consume just
about anything that one would house in a reef display while the Emperor will be
a little more discerning. LPS corals, some soft corals, anemones, and clams are
more at risk in comparison to SPS or the more noxious soft corals. If you
attempt to use any such fish predator, be sure to train it properly by feeding
it pest anemones while in quarantine before introducing it into the infested
display. This way, you will know before hand if you will have an assistant in
your battle against the anemones or merely a beautiful addition to your display
which may also nibble on desirable organisms while ignoring the targeted pests.
The Red- Legged Hairy Hermit Crab,
Dardanus megistos, has also been recommended as an Aiptasia predator. While they do seem to eat
Aiptasia I am generally reluctant to place hermit crabs in my reef display.
All hermit crabs, and crabs in general, are opportunistic omnivores. That means
they will basically try to eat just about anything they happen upon that is
edible. This can run the gamut from desirable algae, mysid shrimp, amphipods,
worms, and even some corals. It is my opinion that few crabs are completely
safe, practical, or recommended for most reef aquariums.
The Lysmata wurdemanni, the
true Caribbean Peppermint Shrimp, will often eat Aiptasia sp.,
but as seen in this picture, they will often also kill and eat desirable
tankmates. Beware of very close look-alikes, especially the
destructive Camel Shrimp.
Lysmata wurdemanni, have been recommended to clean up
in display tanks. Basically, they work sometimes. I have had tanks where I
introduced a few and within weeks all the
were gone. In other instances, they don’t seem to eat any
Aiptasia , and instead concentrate on stealing food from fish and corals. I
have even witnessed them attacking and eating small feather dusters and
Astraea snails, so I would say these
are at best hit or miss. The one thing to watch out for if you select this
method is to be sure that you get the true Peppermint shrimp. You are
looking for Lysmata wurdemanni. These
are collected out of the tropical West Atlantic Ocean/Caribbean. There are
several other shrimp that are also imported and are occasionally mistaken for
Peppermint shrimp. The most commonly available is
Rhynchocinetes durbanensis, also called the Camel Shrimp or Dancing Shrimp
because of the distinctive hump on their back.
These are easy enough to distinguish, though. Additionally, there are two
other species of Lysmata shrimp that are occasionally available and much easier to
confuse with the true Peppermint shrimp.
Lysmata rathbunae and Lysmata
are similar and alleged to be not as likely to consume
Aiptasia. Both of these also hail from cooler water, so there is some
concern for their long-term viability in typical warm water reef displays.
Kalkwasser and Joe's Juice are
effective chemical means used to control pest anemones.
This is a newer product to enter the
market. You are supposed to squirt, or coat, the pest anemones you wish to kill
with its chalky white liquid. I have found it works pretty well. It takes
multiple applications as with the first use it seems to merely knock down the
anemones. In my experience, they come back albeit smaller after the first
exposure. Hitting them numerous times can completely destroy the pest. The
biggest drawback to this method is how tedious it can be if you have a number of
pest anemones to destroy. It is also comparably expensive to other chemical
means such as kalkwasser. You only get a small 20 ml container of the chemical
along with an application syringe upon purchase for around $7.00 from various
online vendors. For comparison, you can almost buy a one pound tub of kalkwasser
powder for about the same money.
Killing pest anemones by either
injecting them with a kalkwasser mixture, or slathering them with a paste-like
slurry of calcium hydroxide is a tried and true method. It is my usual
preference, but it can be quite tedious if you need to eradicate many anemones.
It generally must be repeated multiple times to affect a complete cure, and you
must be careful when applying it for fear of collateral damage to sensitive
cohabitants that are nearby. On the plus side, many hobbyists already have
calcium hydroxide on hand for use to maintain/supplement calcium and alkalinity.
Also, if you are already dosing limewater any excess kalkwasser is merely going
to contribute to your calcium concentration versus some other targeted poison
which is left to drift with the currents throughout your tank.
There is a whole host of other
aqueous solutions that people have used to attempt to kill pest anemones with by
means of injection: boiling water, hypersaline water, lemon juice,
muriatic acid, pepper-based liquids, and vinegar are just a few that come to
mind. The first hurdle with any of these injectables is actually trying to stick
one of these anemones with a needle. The anemones won’t stand still while you
attempt to jab them. They usually retract down deep into a hole whenever you
even get close to them making injections a challenging activity, to say the
least. Secondly, even if you manage to get lucky and properly inject and kill
one, how many more do you have to eliminate?
You should be able to see that this is a rather daunting task if the tank
is overrun with pests. Lastly, with the exception of boiling water and
hypersaline water, I am reluctant to add these other chemicals to my tank.
Kalkwasser is simply calcium hydroxide and is a preferred method of delivering
and maintaining calcium and alkalinity. Hence, small excesses of this compound
which are carried away in the currents of your aquarium are not likely to have a
negative impact. Although, if you add an extreme amount of kalkwasser, you can
spike the tank’s pH to dangerous levels and harm the occupants.
Physical Means of Control
Do your best Tony Soprano
impersonation and say, “Fagetta baat it.”
Siphoning, scrubbing, cutting, and most other attempts to physically remove pest
anemones are only going to end up propagating them. Any tiny portion of the
anemone that is left behind or cut from the parent and blown away in the
currents can grow to become another new pest.
I have even seen and read of people
trying to smother pest anemones with underwater epoxy. The few instances I have
actually witnessed this attempted were not successful. Even if this worked, you
would be left with a bunch of unsightly patches of underwater epoxy all over
your display. Who wants that?
I would be remiss if I did not
mention something else concerning these pest anemones. They are like other
anemones, and really cnidarians in general; they cannot survive on light and the
products of photosynthesis alone. They must be fed to live, grow, and multiply.
In many instances, a proliferation of pest anemones should also be a wake up
call to the aquarist to reexamine their husbandry techniques. Over feeding or
inappropriate feeding, dosing the tank with suspect additives and invertebrate
foods, and poor nutrient export processes are all likely contributing factors in
many instances where these pests get out of control. A thorough, thoughtful
retrospective on the care you provide may yield some additional measures that
you can institute or perhaps some refinement of your current practices to help
you in this battle by starving the creatures into submission.
So, what should you use?
That is hard to say. Much of making this decision has to do with your
particular set of circumstances and what kind of work you want to put into it. I
can tell you what I would use. Berghia nudibranches are far and away one of the best choices
because they are both 100% safe and effective when used properly. They are
guaranteed to eat Aiptasia
and won’t bother anything else. You can even make a few bucks on them because
they breed so readily, have a high demand, and command a good price.
Copperbanded Butterflyfish and Peppermint Shrimp are not bad choices, either.
Both work sometimes. You just have to observe your animals carefully and be
prepared to remove these Aiptasia
predators if they start preying upon other desirable organisms. Lastly, Joe’s
Juice and kalkwasser are both moderately effective, although more work than the
various biological methods. Plus, kalkwasser is readily available and much
cheaper than Joe’s Juice, hence it gets my recommendation for a chemical means
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in the Marine Aquarium.” Tropical Fish Hobbyist (April
2004): pages 137-145.
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