Nearly every reef-keeper can tell stories of the hours spent looking at their new tank, watching to see what new life will emerge from the liverock. It’s almost a magical time, especially for the new reef-keeper, as the wonders of the sea slowly unfold within the small glass world we’ve created for it.
Most stories that involve Aiptasia begin in the same way. Suddenly, a new little anemone is spotted on a newly added piece of liverock or live coral fragment, just a ‘baby’…
But soon that one ‘baby’ becomes two, then five, then many more.
True to their name, Aiptasia sp. Anemones (which means ‘beautiful’) are elegant creatures, but they are also invasive and aggressive competitors. Left unchecked, they will often totally over-run an aquarium.
Aiptasia have developed to be survivors. They reproduce both sexually and asexually, and are capable of regenerating and entire creature from a single cell. In addition, they are armed!
When Aiptasia are disturbed (either by a passing fish or invertebrate) they eject dangerous white stinging threads called acontia that contain venomous cells called nematocyst. These nematocysts are capable of delivering a potent sting that can cause tissue regression in sessile corals, immobilize prey, and even kill unlucky corals, crabs, snails or fish.
Considered by many experienced reef enthusiasts as a pest (or worse), early identification and action are necessary to quickly remove Aiptasia from your tank before they reach epidemic proportions - making control/removal far more difficult.
The first step to controlling an Aiptasia infestation is proper identification. It does little good to invest time and money into a solution to the wrong problem.
Aiptasia anemones can be identified by their resemblance to miniature palm trees, with a polyp body (the coelenteron) up to 5 cm (2 in) in length and an oral disc up to 2 cm (3/4 in) across bordered by a mixture of a few long and many short tentacles (up to 100 tentacles may be present) positioned in narrow rings on the outer margin of the oral disc. The tentacles are long slender protrusions that form sharp points at their ends.
At the center of the oral disk is the mouth in the form of an elongated slit. At the base of the polyp body is the pedal disk which functions as an anchor for the anemone as well as a means of asexual reproduction.
Coloration of Aiptasia is due to the presence of Zooxanthellae (microscopic photosynthetic dinoflagellate alga - species Symbiodinium microadriaticum). For this reason specimens that live in well lit areas are usually light greenish brown to dark brown, with those in areas which receive less light are typically medium to light brown or tan in color and those from low light areas tending toward a transparent appearance. Often an anemone's column or stalk is lightly marked with parallel longitudinal lines. Sometimes white or light green flecks may also be present near the tentacles, and it is not unusual for juvenile specimens to be entirely covered with them.
Like all members of the Cnidaria phylum, Aiptasia have the ability to sting for both offensive and defensive purposes. All Cnidaria have a stinging cells called cnidocytes, each of which contains a stinging mechanism, cnidae or nematocyst. Aiptasia possess both cnidocytes on their tentacles as well as specialized cinclides around the lower part of the column (small blister-like protrusions) through which it expels acontia.
Acontia are threadlike defensive organs, composed largely of stinging cnidocytes cells which are expelled out of the mouth and/or the specialized cinclides when the Aiptasia is irritated. (Many anemones do not have acontia or cinclides but Aiptasia do.)
The nematocysts of Aiptasia have a toxin that is more potent than the majority of corals kept by the hobbyist (with the Elegance Coral - Catalaphyllia jardinei being one exception) and can cause tissue regression in sessile corals, immobilize prey, and even kill unlucky crabs, snails or fish.
As an added defensive mechanism, Aiptasia can also withdraw into tiny holes in your liverock if threatened. Taking advantage of this trait, one can poke a suspected Aiptasia anemone with a probe and observe its reaction. If it rapidly pulls itself downward (as opposed to folding in on itself), it’s likely an Aiptasia.
There are two main anemone hitch-hikers that the reef aquarist is likely to encounter. The first is the Aiptasia sp. Anemone; the second is the Manjano Anemone - Anemonia manjano (formerly majano and commonly referred to as Majano Anemone, Anemonia Majano, Manjo Anemone). It is important to be able to distinguish between the two as some of the remedies for an Aiptasia infestation will not work as effectively (or at all) with the Manjano Anemone.
The Manjano anemone is also considered a ‘pest’ and is equally capable of out-competing and overwhelming a reef tank. Like the Aiptasia Anemone, it has a pedal column with a sticky foot that is use to attach itself to the rock surface, and an oral disk surrounded by tentacles. The color is typically greenish brown to tan with the tentacles having white or light tips. This anemone can grow up to 3 cm (1.5 in) in diameter.
The main difference between the Manjano anemone and the Aiptasia is that the tentacles of the Aiptasia are typically slender and very pointed at the tips, while the Manjano anemone has ‘stubby’ tentacles that are often bulbous at the tips.
The photos above demonstrate this difference. The first image is a close-up of a Manjano anemone. In the second photo, you can see the Aiptasia in the lower-left and the Manjano in the upper-right. Notice the difference in the shape and size of the tentacles.
The Aiptasia genius (first described by J. L. Chr. Gravenhorst in 1831) is comprised of 17 accepted species, with the most common being:
Members of the Aiptasia genus are found in tropical and subtropical oceans worldwide, including the Western Atlantic Ocean, the Caribbean from Bermuda to South America, the North Western Pacific east to Hawaii, the Mediterranean Sea and the Red Sea. Most of the 17 species of Aiptasia are distributed in the Atlantic Ocean and Mediterranean Sea and only Aiptasia californica and Aiptasia pulchella have been reported in the Pacific Ocean.
Aiptasia Anemones are found in shallow waters along protected coasts and along intertidal rocky or mangrove lined shorelines as well as in deep water areas with good to strong tidal flows. They will also form dense colonies in areas of shallow water, sometimes so dense they look like solid sheets. They are found alone attached to rubble, mangrove roots, dead corals, and other hard substrates. Aiptasia sp. are able to withstand a relatively wide range of salinities, light-levels and other water quality conditions. All species are commonly found with liverock.
Cnidarian species are found in one of two body forms: the polyp and the medusae. In the case of Aiptasia, the body form is the polyp. The body is composed of a pedal disc with which Aiptasia attaches to the substrate, a smooth and elongated body column and an oral disc which bears the mouth and long stinging tentacles.
Like all members of the phylum of cnidarians, all Aiptasia species utilize a tissue level of organization, meaning that they possess specialized cellular collections that perform biological function and lack structured organs and organ systems.
Aiptasia are composed of two cell layers: an epidermis and a gastrodermis. The two cell layers are cemented together by an acellular matrix known as mesoglea. The gastrovascular cavity of Aiptasia sp. is partially subdivided by radially arranged septa (or partitions) containing string-like acontia and gonads along their inner edge.
Symbiotic single celled dinoflagellate algae, Zooxanthellae, are found within the gastrodermal cells. Both the acontia and epidermis harbor cnidocyte stinging cells.
Aiptasia swim by ciliary action in spirals or by crawling on its side, progressing at about 4 cm per hour. To do this, the pedal disc is pushed forward by contraction of circular muscles, the trunk shortened by contraction of longitudinal septal muscles, and the oral disc pulled along after. Many times Aiptasia will simply opt to disconnect and float around, or swim by moving in a spiral motion, until they find a new spot to adhere too.
Aiptasia contain zooxanthellae, or symbiotic dinoflagellate algae, which produce oxygen and fix carbon by photosynthesis. Much of the carbon fixed is released to the anemone, aiding in its energy needs while the Aiptasia, in turn, supplies the algae with nitrogen and phosphates in the form of ammonia waste by-products. Anemones also feed on zooplankton as well as filtering nutrients and other plankton from the water column.
In the reef aquarium, Aiptasia will happily eat fish food and coral foods when the opportunity presents itself. Many times Aiptasia can be found growing in an overflow because it can easily take in fish food that has moved into the overflow with the circulating tank water.
Reproduction is both sexual and asexual.
Aiptasia reproduce asexually by pedal laceration. Small masses of cells are pinched or torn off the margins of the pedal disk forming small buds. These grow slowly into buds and within a week or two after completely separating from the foot the bud develops a mouth and small tentacles and begins to feed on its own. Some of these clones will release and be distributed in the water column to colonize other locations. Additionally, Aiptasia demonstrates a preferential tolerance to its own clones and will not sting them. This allows large groupings of Aiptasia clones to form as a result of asexual reproduction.
Unlike some cnidarians, Aiptasia are extremely successful in generating or regenerating an entire animal from a single cell. It is because of this that physical removal is so difficult to perform successfully.
Aiptasia increase asexual reproductive basal lacerates during times of extreme stress such as low oxygen, decreased circulation during power failures, low lighting situations, attack by predators or when the aquarist attempts physical or chemical methods of removal.
While there is little scientific documentation on the sexual reproduction within Aiptasia, general observations indicate the sexual reproduction may occur in two forms.
In the case of the well-studied Aiptasia pallida and Aiptasia pulchella, individuals are dioecious, meaning that individuals are of separate sexes. During spawning, anemones release their gametes into the water where fertilization occurs. The resulting zygote becomes a free swimming planula larva which eventually settles onto a suitable substrate and undergoes metamorphosis to become a small polyp. Newly produced larvae are aposymbiotic meaning they do not contain symbionts. The larvae or newly settled polyps acquire symbiotic algae from the environment.
In certain species of Aiptasia fertilization may be internal, in the coelenteron. Male gametes are released from male Aiptasia into the water column. These gametes are non-buoyant and settle to fertilize the female gametes within other Aiptasia. These gametes develop internal to the Aiptasia into Planula Larva, receiving nourishment from the hosting anemone. When conditions are optimal (light and nutrients are high), or during physical attack (as when an aquarist is attempting to remove them), these larva are released into the water column to start growing and colonizing other parts of the reef.
There are many methods that have been developed for the removal of Aiptasia, everything from simply scrapping them off to using a blow torch to burn them off. Below is a list of the more common (and safe) methods of dealing with Aiptasia. Each solution has its advantages and disadvantages and may not may be right for your situation or compatible with your tank inhabitants, so read each carefully before deciding which approach to pursue.
While for many this may be their first reaction, extreme care should be used in this method. In attempting to remove Aiptasia anemones physically, every cell must be removed. You can not simply cut them up or brush them off. All that will result is many more Aiptasia returning a few weeks later. Since Aiptasia reproduce (quite effectively) by pedal laceration, tearing or breaking them up only serves to help them multiply much more quickly.
However, in the case of large Aiptasia that are too big for other a natural Aiptasia predator to eat, this method may be necessary. It won’t eliminate the Aiptasia, but those that grow back will be much smaller at first and a more manageable meal.
If physical removal is attempted (though it is discouraged) it is important that the remains of the Aiptasia be removed from the tank to prevent decomposition from introducing excess nutrients into the water.
This method is cheap.
This method is basically a waste of time. It is nearly impossible to scrap every last cell of an Aiptasia off from the liverock. Additionally, Aiptasia are often anchored in small crevices within the rock into which they retract the moment you begin scrapping. This makes it impossible to remove every last piece of the organism, and each piece left will undoubtedly grow a new complete Aiptasia.
Additionally, under such stress, certain species of Aiptasia will release their planula (offspring) into the water column which will settle on the rock-work and grow new Aiptasia.
Chemical removal involves the application of a chemical agent on to or injecting it into the Aiptasia. There are many concoctions that have been put forth as ‘cures’ for Aiptasia and each works to varying degrees. But it is not uncommon for these treatments to actually make your aiptasia spread even worse. Use these products with caution.
The important point to note with chemical removal is that most of the ‘remedies’ introduce chemicals into your reef tank that may negatively alter your tank chemistry, especially if applied in large doses.
These chemical treatments are harmful to ALL life, despite the claims. If the chemicals are injected or applied to a coral, or any other living creature in your tank, it WILL harm it, so care must be taken when applying these chemicals. Additionally, many of these chemical solutions are harmful to YOU! So if you choose to implement any of these methods make sure you protect yourself by wearing appropriate gloves and eye/face protection, and if they contact your skin, eyes or are ingested, contact your local poison control center immediately.
When using chemical treatments, always be prepared for large water changes in the event that the treatment you choose results in the poisoning of your reef inhabitants. Sufficient salt water should be on hand to allow for at least a 50% water change if negative affects are noticed with any of your reef inhabitants. Also, major water parameters should be tested before and after treatment to ensure that there are no adverse affects to water quality.
These remedies are concocted from typical chemicals around the home/reef.
Bottled Lemon Juice Concentrate – This treatment relies on the weak acetic acid within the lemon juice to kill the Aiptasia. The lemon juice is injected into the Aiptasia allowing the acid to kill it from the inside out.
Care should be used as the lemon juice can irritate coral tissue if inadvertently applied to it.
Results: If injected properly, this method has a relatively high kill rate, but injecting inside the anemone is extremely difficult and often portions of the anemone remain to regrow, making the condition worse.
Calcium Hydroxide – Injecting Aiptasia with calcium hydroxide (often referred to as Kalkwasser, Kalk or Pickling Lime) in a concentrated solution is one of the most common chemical methods used. A derivative of this solution involves mixing the Calcium Hydroxide (a powder) with just enough water to make a thick paste, like the consistency of toothpaste. The paste is then applied over the Aiptasia using a turkey-baster or turkey injector or simply spread with a blunt applicator.
Important: Concentrated Calcium Hydroxide is a medium strength base and will kill or severely injury anything it is applied to. Also, attempting to apply this solution to too many Aiptasia at once may have a negative affect on the pH and alkalinity within your tank.
Results: This method works, but is not very effective unless done properly. The injection of the Kalk is less effective than the application of the paste, however it is very difficult to get the paste to cover the anemone especially in tanks with moderate to high water flow or where the anemone is attached inside a rock crevice or is not attached to a horizontal surface.
Sodium Hydroxide – Also called lye or caustic soda, Sodium Hydroxide is a principal agent in oven cleaners.
|WARNING! - Solid sodium hydroxide or solutions of sodium hydroxide will cause chemical burns, permanent injury or scarring if it contacts unprotected human or animal tissue. It will cause blindness if it contacts with the eye. Protective equipment such as rubber gloves, safety clothing and eye protection should always be used when handling the material or its solutions.
Dissolution of sodium hydroxide is highly exothermic, and the resulting heat may cause heat burns or ignite flammables. It also produces heat when reacted with acids. It is corrosive to glass and some metals. Keep away from aluminum.
In this 'remedy?' the powered Sodium Hydroxide is mixed with water to form a paste which is then applied to the Aiptasia.
Results: This is a biocide and will kill Aiptasia if applied correctly. General results indicate a high kill rate for exposed anemone with success rates dropping to 50% where Aiptasia is anchored in a crevice in the rock or one vertical surfaces.
Hot Boiling Water – This method involves ‘blasting’ the anemone with boiling water from a syringe. It does not work very well, and your chances are pretty slim of it helping to get rid of the Aiptasia.
Other ‘Remedies’ – There are numerous other remedies (such as Hot Sauce, strong acids, boiling Kalk or Hydrogen Peroxide etc.) touted as ‘successful’ against Aiptasia. Most of these have very limited success rates or are too dangerous (both to you and your tank inhabitants) to even mention here.
There are several commercially available treatments for Aiptasia. All of these require direct application to the Aiptasia either by injection into the body of the anemone or by ‘feeding’ the anemone. The latter method requires application of the chemical to the oral disk of the anemone.
Some manufactured chemicals include:
It should be noted that these products are typically a derivative of one of the above mentioned solutions – often containing a caustic chemical to kill the Aiptasia together with additives that either encourage the Aiptasia to feed (thus ingesting the chemical) or that help the product adhere to the anemone (like a glue). In situations where the Aiptasia is easily reached, these chemicals may have good results. However, in hard to reach areas, or where the Aiptasia can withdraw into a crevice, their effectiveness diminishes markedly.
Careful research should be done to ascertain the contents of any commercial product used. They will affect your tank parameters and will harm any other life they come in contact with within your tank.
These methods are relatively simple and cheap if only a few Aiptasia are present and many have reported some success. Application is a bit tricky, especially if an Aiptasia is not sitting on an easily accessible horizontal surface.
Chemical treatments make the most sense when treating a very small number of Aiptasia in a controlled area (as in a quarantine tank) where the Aiptasia can be easily reached.
First, these methods introduce chemicals into your system that will affect the stability of your tank. Whether the solution you choose is an acid (like lemon juice) or strong base (like sodium hydroxide), it will have an effect on your tank pH at the minimum. The amount of this effect is dependant on the amount of chemical used as well as the size of the tank. Additionally, these chemicals add organic material (either directly or from the remains of the Aiptasia) to your water that will result in an increase in nutrients.
Injecting Aiptasia is much easier said than done. The moment the needle touches the anemone, it will retract into the rock. It can also be difficult to reach many of the Aiptasia anemones growing on the rock-work without removing the rock they are attached to.
Finally, typically the injection is insufficient to completely kill every cell of the Aiptasia, resulting in more Aiptasia growing from the remains of those treated. Some of these treatments have a ‘blast’ effect that results in the Aiptasia fragmenting and leaving living pieces free to float and settle elsewhere in the tank.
Additionally, under such stress, certain species of Aiptasia will release their planula (offspring) into the water column which will settle on the rock-work and grow new Aiptasia.
It should also be noted that some of the chemicals that claim to rid your tank of Aiptasia do not actually work or contain very, very harmful compounds. You need to research specific brands if you decide to use a commercially available product.
There also have been reports of sudden coral deaths associated with the use of a chemical means of removal. While the exact cause of these sudden deaths is currently unknown, some have theorized that it may be related to the sudden release of dopamine and serotonin which can be found in both the tentacles and the body of the Aiptasia. Dopamine affects the central nervous system, serotonin brain activity and balance. The purpose/function of these chemicals in Aiptasia is currently unknown.
All ‘pests’ have a natural predator to maintain balance. This is true of Aiptasia as well. There is a whole spectrum of animals that eat Aiptasia anemones to varying degrees. It should be noted that only one of these predators (the Berghia nudibranch) has specifically evolved to eat ONLY Aiptasia. As such, it is the most motivated predator available to rid your tank of this pest. All other predators listed below have shown an affinity for Aiptasia, but typically it is a meal of last resort.
When selecting a natural predator of Aiptasia, it is important to match its habitat requirements to those of your particular reef environment. Not all predators are suited for your tank’s environment. Failure to use care in this selection could be detrimental to either the predator added to your tank, or your current tank inhabitants (or both).
The Berghia Nudibranch is a nudibranch from the Florida Keys region of the west Atlantic Ocean (formerly known as Berghia verrucicornis and recently reclassified as a new species Aeolidiella stephanieae) and are by far the most popular choice, because they are 100% safe, and effective when used and cared for properly. Berghia eat only Aiptasia anemones, nothing else. Lacking Aiptasia to consume, they will die, thus they are the most ‘motivated’ Aiptasia predator. While the smallest of the Aiptasia predators, they are the most efficient, consuming the entire anemone, including the entire pedal disk and any planula within. They can crawl all over your tank to eat the Aiptasia you see and the ones you do not see. If acclimated and added to a well maintained tank, they are hardy invertebrates. Occasionally they reproduce to help speed up Aiptasia eradication.
Weaknesses: It takes weeks to months for Berghia to eat heavy Aiptasia infestations especially if you do not get the correct number of Berghia for your problem. If the Berghia are not at least 1/4 inch, they should be maintained in a small tank or a container of at least 1 gallon of water until they grow larger before they are placed in a display tank.
Predators: Possibly peppermint shrimp, nocturnal scavenging fish including fish in the coris wrasse family; to a lesser extent, under-fed large brittle or serpent stars, Emerald and Sally Lightfoot crabs and coral banded shrimp.
Other Prey: None
There are a few hermit crabs that have been reported eating Aiptasia. However these crabs are not reef safe. One such hermit crab is the White Spotted Hermit Crab (Dardanus megistos) which has been reported to consume Aiptasia. However this crab is extremely aggressive to other tank mates (including other hermit crabs). Reaching an adult size of 8 inches, this crab is seldom an appropriate addition to most reef aquariums.
NOTE: Dardanus megistos is sometimes referred to as the Red Legged Hermit –this is NOT the same as the Red Legged Hermit Crab commonly sold which is a different species - Clibanarius sp.
Weaknesses: Crabs are opportunistic feeders. They will eat what is available, and will always choose the more tasty food over the Aiptasia. Thus, in tanks with excess feeding or other readily available feeding opportunities, these crabs will tend to ignore the Aiptasia.
Predators: This crab has few predators within the common reef tank due to its aggressiveness and large size. However, some aggressive tank-mates may prey on this crab, including some species of eels etc.
Other Prey: It is known to feed on tube worms, mollusks, some corals and fish. It will also eat algae. Will attack and kill fish, snails and other hermit crabs (even its own species).
The Peppermint Shrimp (Lysmata wurdemanni), have mixed reporting concerning Aiptasia consumption. Be aware that there is some confusion in the trade regarding this species and other Lysmata species. These other species are not known to eat Aiptasia, so be carefully when purchasing. Also the Camelback shrimp (Rhynchocienetes uritai) is often misidentified or misrepresented and sold as a Peppermint Shrimp. Camelback shrimp do not eat Aiptasia.
Weaknesses: Shrimp are also opportunistic feeders. They will eat what is available, and will always choose the more tasty food over the Aiptasia (often stealing food directly from the mouths of coral and other ornamental anemones. Thus, in tanks with excess feeding or other readily available feeding opportunities, these shrimp will tend to ignore the Aiptasia. Reporting’s of success with Aiptasia control are completely mixed, which may be due to the mix-up in species designation between other members of the Lysmata genus or due to the availability of other food sources.
Peppermint shrimp will also most likely not attack large Aiptasia (anything over an inch tall). In these cases, it may be necessary to physically remove large specimens and allow the shrimp to ‘clean up’ those that re-emerge as smaller anemones.
Reports of peppermint shrimp destroying corals and even ornamental anemones are quite common. Being a nocturnal feeder, this damage often goes unnoticed until significant damage has been done. If you have expensive corals in your tank, especially large polyp stony corals, you may not want to trust peppermint shrimp.
Predators: More aggressive tank-mates may prey on this shrimp, including some species of wrasse.
Other Prey: Shrimp are opportunistic scavengers and will eat anything available.
NOTE: If you tried Peppermint shrimp and didn't get the results you expected, catching them can be easy using a simple DIY Shrimp Trap.
There are several fish (listed below) that have been reported to consume Aiptasia. While not the major component of their diets (nor the preferred one) they will graze on the anemone. Care should be taken in selecting a fish as many of these are NOT reef safe and have been reported to nibble on coral polyps.
One special note on the Copperbanded Butterfly fish (Chelmon rostratus). This fish is extremely difficult to acclimate to a new tank. Most specimens purchased are diseased and die shortly after purchase. In addition, they are shy methodical eaters that can be easily bullied by more aggressive tank mates resulting in their starvation and eventual death.
Weaknesses: These fish are not reef safe and may nibble on or attack certain corals, clams or ornamental anemones. Care should be taken in researching each fish to determine its dietary needs, compatibility with other tank mates and degree to which it is compatible with coral within the tank.
Most of the fish suggested will browse on various types of soft and stony corals, zoanthids, sea mats, and polyps.
Many of the animals listed naturally feed on various types of both sessile and motile invertebrates, such as other sea anemones, feather dusters and other tube worms, clams, sea urchins, and crustaceans.
So whether you have spotted your first Aiptasia anemone, or you’re the unlucky owner of dozens of them, there is hope. There are many options for the control and removal of Aiptasia from your reef tank, some being more successful than others.
Aiptasia infestation is a common problem in saltwater aquariums. Chemical control methods can be used, but please use this as a last resort and do significant research before adding any particular brand of chemical into your tank.
So, whether you choose a natural cure for Aiptasia control (like the Berghia nudibranchs shown to the left), or use one of the listed chemical methods, with patience and diligence, these invaders can be overcome.