The colorful Adhesive Sea Anemone has a distinctive look… often described as a Pizza Anemone!

The Adhesive Sea Anemone, Cryptodendrum adhaesivum, is easy to identify because of its unique ‘pizza-like’ or carpet appearance. Its wide oral disc has two types of tentacles, and the two forms differ in coloration. In the center it has short skinny sticky tentacles that are often multi-branched with fat bulbous tentacles on the outer rim. With these contrasting shapes and colors it resembles a pizza with a thick crust, or a carpet with a binding around the edge. Thus it is commonly called the Pizza Anemone, Pizza Sea Anemone, and Nap-Edged Anemone.

The tentacles of this anemone are very sticky and have potent stinging cells, hence the common name Adhesive Sea Anemone as well as Sticky Carpet Anemone. Be careful in handling it as it will cling to, and sting, any unprotected skin it comes in contact with, leaving welts. With its potent sting it can also be a hazard to careless fish or corals in the aquarium.

This anemone became very popular, very fast, a few years ago. Prior to that they weren’t often seen in the industry because of a propensity to tear when being moved. They are beautiful animals with colors as numerous as the rainbow, so the reason for their popularity is obvious. These colorful combinations along with the tentacle shapes give it a decorative appearance. Colors can range from blue and gray, pink and yellow, gray and purple, and brown and green. Sometimes there are also patches of a 3rd color within the oral disc.

The Adhesive Sea Anemone is not only attractive, but it is relatively hardy when provided the right environment. They live in shallow waters only 3 to 20 feet deep. They are found in rock crevices or underneath stones where sand or coral gravel is piled up. Keeping your anemone in a properly sized aquarium with moderate lighting and plenty of food will help it live a long life.

For more information about Clown Fish anemones, see:
Facts About the 10 Clownfish Hosting Sea Anemones

Adhesive Sea Anemone, Cryptodendrum adhaesivum & Porcelain Crabs
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Great video showing two beautiful animals.

The Adhesive Sea Anemone, also called the Sticky Anemone is a host to a wide variety of marine life. They host clownfish, some crabs and damsels. They resemble a pizza, having what looks like an outer crust and a contrasting center. Provide 100 gallons, bright lighting and clean water. The tank should be mature, around a year old and plenty of space for their eventual 12″ size. Target feed your anemone a variety of minced foods on a regular basis.

Adhesive Sea Anemone, Cryptodendrum adhaesivum in the wild
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Massive mature anemone hosted by ornary striped damselfish!

This video give some perspective as to the size that the Adhesive Sea Anemone can grow to. They are being hosted by 2 clownfish and are being rivaled by a larger black Domino Damsel and some juveniles for the spot! Do not rely on your clownfish or damsel to feed your anemone enough food. In captivity, there is not the same amount of zooplankton as there is in the wild, which they feed on, so you will have to feed them regularly.

Adhesive Sea Anemone – Quick Aquarium Care
  • Minimum Tank Size: 100 gal (379 L)
  • Aquarist Experience Level: Intermediate
  • Temperament: Aggressive
  • Temperature: 72.0 to 80.0° F (22.2 to 26.7&deg C)
  • Size of organism – inches: 4.0 inches (10.16 cm)
  • Diet Type: Carnivore
  • Suitable for Nano Tank: No

Habitat: Distribution / Background

The Adhesive Sea Anemone Cryptodendrum adhaesivum (previously Stoichactis digitata) was described by Klunzinger in 1877. The Cryptodendrum genus, a member of the Thalassianthidae family, contains only this one species. This species is not listed on the IUCN Red List. Some other common names they are known by are Sticky Carpet Anemone, Pizza Anemone, Nap-Edged Anemone, and Pizza Sea Anemone.

Cryptodendrum adhaesivum is found in the Red Sea, Maldives and Thailand, then east toward Micronesia, Polynesia, southern Japan, and Australia. They live in shallow waters only 3 to 20 feet (1-5 m) deep. These are solitary anemones found in rock crevices and among stones or coral rubble. They spread themselves out over the rocks or in-between them. This living “pizza” is occasionally found with one species of clownfish, the Clark’s Clownfish A. clarkii. They are also found associated with a couple species of shrimp from the Thor and Periclimenes genera.

Adhesive Sea Anemone feed on zooplankton and other prey in the water. They use venomous cells, the nematocyst found in their tentacles, to catch prey and also to sting and deflect any possible threats or attacks. Some predators can be other anemones, nudibranchs, sea stars and some angelfish.

  • Scientific Name: Cryptodendrum adhaesivum
  • IUCN Red List: NE – Not Evaluated or not listed


The average size of an Adhesive Sea Anemone, or Pizza Anemone, is around 2 to 4″ (5 – 10 cm) but they can grow up to 12″ (30 cm). It is unknown how long they live. Some anemones can be hundreds of years old in the wild, and in captivity some have been known to last 80 years or more.

These anemones have a pedal column with a sticky foot at the bottom that they use to adhere to various surfaces. They like to flare out over rocks or in between them. They also use the “foot” to move around if conditions are not ideal. The pedal column has rows of verrucae, small bulges that also have stinging cells. These bumps can be white, orange, or yellow. The column may also have flicks, lines and spots on it.

Characteristic identifiers of the Adhesive Sea Anemone are their 2 different forms of dense sticky tentacles. The tentacles can be up to 5 mm in length. Those in the center of the oral disc are narrow with several branchlets at the end, looking almost like a little hand, and are up to 5 mm in length. The tentacles at the edge are bulbous and about 1 mm in diameter. The inner tentacles are a different color than those on the edge creating a colorfully contrasting oral disc. Color combinations can be blue and gray, pink and yellow, gray and purple, and brown and green. Sometimes there are also patches of a 3rd color within the oral disc.

The anemone’s mouth is small, about 1 cm in diameter, and is in the center of the oral disc. It is usually a contrasting color to the disc as well, in colors like yellow, white green, or violet. The mouth should be closed and tight, and will open when hungry, having an oval look. A gaping mouth is a warning signal. The C. adhaesivum take food in and expel waste through this same opening.

  • Size of organism – inches: 4.0 inches (10.16 cm) – Average size of the Adhesive Sea Anemone is around 2 to 4,” but they can grow up to 12″ (30 cm).
  • Lifespan: 80 years – Though the lifespan is unknown, some anemones have been known to live 80 years or more in captivity, and hundreds of years in the wild.

Difficulty of Care

The Adhesive Sea Anemone is easy to moderate to care for, being relatively hardy when provided the right environment. They do have moderate lighting needs and must be in a large enough aquarium to satisfy their ultimate size. Putting an anemone in a new tank can result in failure. The tank should be at least 8 to 12 months old and stable before adding your new anemone.

When choosing your Adhesive Sea Anemone, make sure the color is good, their mouth is not gaping open, and their foot and tentacles are sticky to the touch. Also, they should be attached to something and make sure there is no damage to the foot area, often a result of pulling the anemone off its surface.

To transfer a C. adhaesivum anemone from another aquarium, use a very thin blunt item, like a credit card, to get under the foot. Slowly nudging it will get the anemone off the glass. Use gloves when handling.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Intermediate

Foods and Feeding

The Adhesive Sea Anemone is a carnivore, but these anemones are well equipped with nutritional alternatives for their well-being. Though they are carnivorous, they are thought to be primarily planktivores in the wild, as they seem well suited to collecting plankton. They also use their venomous cells or nematocyst found in their tentacles to sting and capture prey. They absorb nutrients from the water around them and consume wastes from resident animals.

In captivity they can be a bit picky about foods, but will generally accept some small meaty foods. Feed your C. adhaesivum finely chopped silversides and smelts, mysis shrimp, brine shrimp, or bloodworms several times a week. You will need to target feed this anemone. The old adage that anemones should be fed once a month is false and has lead to many deaths.

It is not necessary for them to be fed by Clownfish they host. When you offer your clowns a piece of fish flesh, they will usually snatch it out of your hand and give it to their host. However, not all clowns are this smart, so don’t depend on the clown fish to feed the anemone. Clownfish hosted with your anemone usually will not be able to sufficiently feed both themselves and their anemone, anyway, with the small quantity of food that is put in a captive environment.

  • Diet Type: Carnivore
  • Flake Food: Occasionally – Carnivore formula. Depends on individual tastes of the anemone.
  • Tablet / Pellet: Occasionally – Carnivore formula. Depends on individual tastes of the anemone.
  • Live foods (fishes, shrimps, worms): Some of Diet – From marine sources as a treat.
  • Liquid Foods: Some of Diet – Liquid foods with larger zooplankton if desired.
  • Meaty Food: All of Diet – Any and all marine flesh.
  • Feeding Frequency: Daily – They should be fed 2 to 4 times per week, more as juveniles.

Aquarium Care

Water changes of 10% bi-monthly or 20% a month are typical. Monitor your water quality for your particular situation and adjust your water changes accordingly. Waste production created by your anemone can be calculated in inches. Basically, every inch of anemone is equal to an inch of fish, so an average sized Adhesive Sea Anemone of 2 to 4″ produces a bioload equivalent to that of 2 or 3 fish small fish.

Purigen and Poly-fiber are great products to help in maintaining water quality. Purigen is a synthetic polymer that removes soluble and insoluble impurities from water at an exceptionally high rate and capacity, helping to control ammonia, nitrites and nitrates. Poly-fiber can be cut and used in sumps, etc.

Although anemones are not as dependent on calcium as stony corals, magnesium and calcium are still needed to keep the pH and alkalinity stable and within the correct parameters. Additions of trace elements are suggested. Phosphates should be kept around 0.03 or less.

  • Water Changes: Bi-weekly – Water changes of 10% twice a month, or 20% a month are typical.
  • Calcium Levels: 380.0 – 450.0 ppm – Helps to balance alkalinity. Aim for 420, or 385 if you are using Seachem calcium.
  • Alkalinity Levels: 7.0 – 11.0 dKH – (2.5 to 3.9 meq/L) Aim for 10 dKH (3.5 meq/l) for reef tanks.
  • Magnesium Levels: 1,250.0 – 1,350.0 ppm – Test magnesium levels and adjust before checking Calcium.
  • Strontium Levels: 5.0 – 15.0 ppm – Aim for 8 ppm.
  • Iodine Levels: – .030 to .060 ppm. Control is not recommended.

Aquarium Setup

A typical live rock/reef environment is best for the Adhesive Sea Anemone. A mature 100-gallon tank with live rock that is at least 9 to 12 months old is advised to increase the successful life span of C. adhaesivum. They are not suited for small nano tanks, since it is hard to keep water quality high and due to their ultimate size.

The Adhesive Sea Anemone will attach to a hard surface and spread out over and in between the rock. Any substrate is fine. They need high levels of lighting, like any anemone, and the water movement should be moderate. A good protein skimmer is a must. Once it is secured and settled, if it is happy it will stay put. If it isn’t happy and is moving around, be sure to check your checking your lighting and water quality. Also, make sure you are feeding it adequately. With all anemones its a good rule of thumb to have all of your pumps covered. Most good quality pumps have guards on them.

  • Minimum Tank Size: 100 gal (379 L) – Tank width is more important than length.
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Amount
  • Substrate Type: Any
  • Lighting Needs: High – Strong lighting
  • Temperature: 72.0 to 80.0° F (22.2 to 26.7&deg C)
  • Specific gravity: 1.023-1.025 SG
  • Water Movement: Moderate
  • Water Region: Bottom

Social Behaviors

All anemones are semi-aggressive because they can be mobile, although a contented Adhesive Sea Anemone will stay put once it has found a place to settle. It has often been suggested to not put anemones in a reef environment since corals cannot move away from the stinging tentacles. Once you get your anemone situated and it has not moved for several months, it might be safe to add other corals. Keep this in mind when stocking sessile inverts. Some predators can be other anemones, nudibranchs, sea stars and some angelfish.

In the aquarium, all anemones need to be at least 2 to 3 feet away from each other. Anemones need to have their own space, otherwise there can be a “chemical” warfare between species. This will usually cause one to not eat, shrink and eventually die. After splitting, anemones will tolerate their own “clones,” and sometimes their own species. If you have 2 anemones that are 6” across, than your tank should be at least 4 to 5 feet long. Having excellent filtration and a large tank, (over 200 gallons) will usually allow 2 anemones at opposite ends to thrive. You can also build a natural blockade, 2 “pillars” with sand in between them, to help prevent them from wandering into each others “space.” Get both anemones when young and let them grow together.

In nature, the Adhesive Sea Anemone has been found as host to only one species of clownfish, the Clark’s ClownfishAmphiprion clarkii, and only occasionally. In captivity, however, it has been known to also host the Tomato Clownfish A. frenatus and the Maroon Clownfish Premnas biaculeatus. In the south central Pacific Islands of Marquesas, it is known to associate with the damselfish Strasburg’s DascyllusDascyllus strasburgi, and it will also live in a commensal relationship with two species of shrimp, the Sexy Anemone ShrimpThor amboinensis and the Pacific Clown Anemone ShrimpPericlimenes brevicarpalis.

If you want your anemone to host clownfish, be sure it is 3 to 4 times larger in diameter than the length of the clown fish you introduce, or it will be ‘loved’ to death. A 4 to 6” anemone with clowns that are introduced at a young age of 1” to 1.5” will work out well. Keep in mind, the more clowns you have translates into more “inches” of fish” for your anemone. It is best to buy the anemone first and give it a few months to acclimate and grow before adding clowns.

  • Venomous: Yes – The Adhesive Sea Anemone may roam and sting sessile corals.
  • Temperament: Aggressive
  • Compatible with:
    • Same species – conspecifics: Sometimes
    • Anemones: Monitor – Space anemones at least 2 to 3 feet away from each other.
    • Mushroom Anemones – Corallimorphs: Monitor – Keep them out of reach of the anemone.
    • Leather Corals: Monitor – Keep them out of reach of the anemone.
    • Zoanthids – Button Polyps, Sea Mats: Monitor – Keep them out of reach of the anemone.
    • Sponges, Tunicates: Monitor – Keep them out of reach of the anemone.
    • Starfish: Monitor – As long as they are reef safe starfish.
    • Feather Dusters, Bristle Worms, Flatworms: Monitor – Keep them out of reach of the anemone.
    • Clams, Scallops, Oysters: Monitor – Keep them out of reach of the anemone.
    • Crabs: Monitor – Only some species of commensal crabs are safe.
    • Snails: Safe
    • Sea Apples, Cucumbers: Threat
    • Urchins, Sand Dollars: Monitor – As long as they are reef safe.
    • Nudibranch, Sea Slugs: Monitor – They may be consumed if they get too close. Some are predators to anemones
    • Copepods, Amphipods, Mini Brittle Stars: Safe
    • Stony Corals: May be aggressive – Keep them out of reach of the anemone.
    • Soft Corals: May be aggressive – Keep them out of reach of the anemone.

Sex: Sexual differences

No sexual difference in appearance is known.

Breeding / Reproduction

The propagating techniques of the C. adhaesivum are unknown at this time. Anemones in general can multiply by sexual and asexual means. One way is using fission, which is when they actually split in half from the foot or mouth to form a clone, although the clone is its own animal, similar to twins. They will also reproduce using male and female sex glands or find another anemone of the opposite sex. Both will release mature gametes into their digestive system, which is then released up and out through the mouth. After this spawning method, the zygote will develop into planktonic larvae or free floating in open waters. They will form tentacles, septa and a pharynx right before they settle into the reef with the mouth pointing upward. This results in the production of ciliated planula larvae. This planula will eventually fall to the sea floor, develop a pedal disk, then begin to grow into a new anemone.

  • Ease of Breeding: Difficult – Has not been bred in captivity.

Ailments / Diseases

Adhesive Sea Anemones are pretty durable once they settle in. Problems are pretty minimal unless your lighting, water movement, feeding and/or water quality is low or inadequate. In that case, your anemone will detach to look for “better conditions.” In general, if your anemone moves, it is not happy. With any change in shape, color, or other indications that there is a problem, you need to check your lighting and water quality.

Some predators can be other anemones, nudibranchs, sea stars and some angelfish, triggers and large wrasses. If there are any non-reef type fish in the aquarium, like large wrasses, look for possible attack marks.


The Adhesive Sea Anemone or Pizza Anemone C. adhaesivum is easy to find in stores and online. The cost online starts at about $60.00 USD (Nov, 2015) and goes up depending on size and color.


Featured Image Credit: Cryptodendrum adhaesivum – adhesive-sea-anemone-2 by Chaoklum Diving, Wikimedia Commons CC SA 4.0 International