The Burrowing Tube Anemone is topped with a crown of tentacles that can extend 14″ above the substrate!

The Burrowing Tube Anemone Pachycerianthus fimbriatus is a large, impressive animal. It grows a cone-like tube that is 6″ in diameter that it can quickly retract onto when disturbed. It also has long feeding tentacles that reach up to a foot high. These tentacles are bioluminescent, glowing in the night light to startle fish that would nibble on them.

This anemone differs a bit from other tube dwelling anemones. Like other burrowing anemones, it has a long, soft, cylindrical body with a pointed foot on one end and a crown of tentacles on the other. It uses its pointed foot to burrow deep into a sandy or muddy substrate where it constructs a hard tube to live in. But it differs from other tube dwellers in that several inches of its tube will sometimes extend above the surface, rather than having its entire tube buried in the sand with just the oral disc and tentacles exposed.

The name ‘ tube dwelling anemone’ is derived from their ability to build a tube to live in. It was previously believed that they created their tube by releasing a mucus, which then become covered with sand. Today however, it is known that they create the tube by releasing threads of a special type of nematocysts called ‘ptychocyst’. The result is a woven fibrous structured of stinging cells that help protect it from attack. Though its tentacles are non-retractable, if it is frightened or disturbed it can instantly withdraw its whole body into the tube for safety.

Burrowing Tube Anemones can make a spectacular display in the aquarium. But because of their requirements, they are difficult to maintain, and are only recommended for the advanced aquarist. These anemones are a cold water species, their normal temperature range is a low 59° – 68° F (15° – 20° C), so the aquarium will need to have a chiller. They also require a good sized aquarium due to their burrowing behavior and ability to expand quite wide. If its needs are met, however, it will reward the aquarist with an interesting glimpse into its secretive world.

Be sure to provide plenty of room for tank mates to keep them out of reach of the anemones stinging tentacles. Several Burrowing Tube Anemone specimens can be kept in a large aquarium, but they are not compatible with other anemone species. Its only known predator is the Rainbow Nudibranch Dendronotus iris, which never actually kills the tube anemone, it just eats and runs, leaving enough behind for the anemone to regenerate.

For more facts about Tube-Dwelling Anemones, see:
Tube Anemone – Burrowing Sea Anemone

Burrowing Tube Anemone, (Pachycerianthus sp)

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Burrowing Tube Anemone manipulating food into it’s mouth

This tube anemone like others in this family are best kept by advanced aquarists. The depths of fine sand, enough oxygen, yet low water flow and constant feeding makes it very hard for the large majority of marine aquarists. They may look great one day but are dead the next. They need a chiller, pristine water quality and lots of room so other corals and fish are not stung.

Burrowing Tube Anemone – Quick Aquarium Care
  • Minimum Tank Size: 50 gal (189 L)
  • Aquarist Experience Level: Expert
  • Temperament: Semi-aggressive
  • Temperature: 59.0 to 68.0° F (15.0 to 20.0&deg C)
  • Size of organism – inches: 12.0 inches (30.48 cm)
  • Diet Type: Carnivore
  • Suitable for Nano Tank: No

Habitat: Distribution / Background

The Burrowing Tube Anemone Pachycerianthus fimbriatus was described by McMurrich in 1910. The Pachycerianthus genus belongs to the Cerianthidae family and contains about 16 species. P. fimbriatusis is found in the Eastern Pacific Ocean from Baja California, all the way up to Alaska. This anemone is not on the IUCN Red List for endangered species. Some other common names it is known for are the Tube Anemone, Burrowing Sea Anemone, Burrowing Anemone, and Tube Dwelling Anemone.

The Burrowing Tube Anemones are cold water, burrowing anemones that are found to depths of 100 feet (30 m), mostly in intertidal areas. They mostly inhabit intertidal area with sandy and muddy bottoms. Zooplankton is their main fare and they are found most populated in waters where the plankton is very dense. Their only known predator is the Rainbow Nudibranch Dendronotus iris, which never actually kills the tube anemone, just eats and runs, leaving enough behind for it to regenerate.

Tube anemones from the Pachycerianthus genus have been known to move across the bottom of the sea floor using their tentacles. They will move over 3 feet or more until they find a spot they like and burrow again. They may also swell up and let the current take them.

  • Scientific Name: Pachycerianthus fimbriatus
  • IUCN Red List: NE – Not Evaluated or not listed


The Banded Tube Anemone can reach 6″ (15 cm) in diameter and the tentacles can reach up to 12″ (30.5 cm). It is unknown how long they live, but in the wild they may live many decades. Some tube anemone species that were introduced into the aquarium at Naples, at its inception, are now over 100 years old.

The Burrowing Tube Anemone has an oral disc with a crown of non retractable tentacles and a mouth in the center. It differs from sea anemones, however, both internally and externally. External differences are apparent. Unlike true anemones, they have 2 different sets of tentacles on their oral disc and they lack a pedal disc foot used to attach to surfaces. They also differ from many true anemones in that they lack zooxanthellae.

The P. fimbriatus has a long, cylindrical, somewhat cone-like body that does not have a foot, but rather a blunt point. They deflate and condense their body to drive the point into sand or mud. Once in the substrate they construct a very long tube. This structure is fibrous, with woven threads of stinging cells to help protect it from attack. When disturbed, they do not form a “ball†like other anemones do to hide, rather they retract into their “tube.†Disturbances that can cause it to retract are sudden illumination, a strong touch, and excessive feeding.

Their tentacles are of two different types. First are the long feeding tentacles arranged in several rows around the margin of the oral disc. These bioluminescent tentacles glow in the night light to startle fish, thus keeping fish from nibbling on them. The other type are shorter labial tentacles over the mouth that are used to manipulate foods. The P. fimbriatusis takes food in and expels waste through its central cavity, or mouth.

  • Size of organism – inches: 12.0 inches (30.48 cm) – This anemone can reach 6″ (15 cm) in diameter with a tentacle length up to 12″ (30.5 cm).
  • Lifespan: 100 years – Though the lifespan is unknown, they have been known to live a 100 years or more in captivity.

Difficulty of Care

The Burrowing Tube Anemone is difficult to care for and should only attempted by advanced aquarists. Even then they have a poor survival rate. They require high quality water and plenty of space. They must be in a large enough aquarium to satisfy their burrowing behavior and ultimate size. They also have a high oxygen need but don’t tolerate turbulent waters, so an ozonizer is the best solution. They will also require a chiller due to their cool temperature needs.

Feeding is another big issue if there is any competition for the meaty foods they need to survive. Zooplankton and other marine tidbits are often consumed by fish and invertebrates before this anemone gets a chance to eat. A species specific tank or one that is very large and very mature is best.

When choosing a P. fimbriatus, make sure the color is good and the mouth is not gaping open. Take special care to make sure there are no tears or injuries. When being removed from another aquarium, a healthy specimen should immediately retract, ejecting the water from its mouth.

Check that the tube is intact and in good condition. Polluted tubes need to be removed before introducing them into the aquarium. If the tube is missing, that can create challenges. Although they can re-grow the tube, it takes a lot of energy that sometimes will deplete the animal into a weakened condition. If they have difficulty creating a tube, you can provide a section of acrylic tubing for it to live in. Place the tubing at an angle in the sand, but be certain that both ends are unobstructed and there are no sharp edges.

  • Aquarium Hardiness: Difficult
  • Aquarist Experience Level: Expert

Foods and Feeding

The Burrowing Tube Anemone is a carnivore and will generally accept small meaty foods in captivity. It can be offered finely minced krill, fish, shrimp and/or frozen or live brine or mysis shrimp. Be careful not to feed with large pieces of food since they will damage the delicate tentacles. This anemone is nocturnal, so feed nightly unless you have a lot of copepods, amphipods and other small prey, then feed twice a week.

  • Diet Type: Carnivore
  • Flake Food: No
  • Tablet / Pellet: No
  • Live foods (fishes, shrimps, worms): Some of Diet – Live brine or mysis shrimp, zooplankton, copepods, and amphipods.
  • Liquid Foods: Some of Diet – Liquid with zooplankton.
  • Meaty Food: All of Diet – Meaty foods must be very small, or they can damage the anemone’s delicate tentacles.
  • Feeding Frequency: Daily – This anemone is nocturnal, so feed nightly, after the main lights go out.

Aquarium Care

Water changes of 10% bi-monthly or 20% a month are typical for most anemones, but the Burrowing Tube Anemone requires more pristine conditions. Their water may need to be changed weekly. 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 a 12″ tube anemone produces a bio-load equivalent to that of four 3″ fish or two 6″ 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. A good protein skimmer is a must.

Although anemones are not as dependent on calcium as stony corals, magnesium and calcium is 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: Weekly – Pristine water conditions are necessary. Although water changes of 10% twice a month, or 20% a month are typical, for this anemone weekly changes may be required.
  • Calcium Levels: 380.0 – 450.0 ppm – Helps to balance alkalinity. Aim for 420 ppm, or 385 ppm 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: 1,200.0 – 1,350.0 ppm – Check magnesium levels and adjust before using Calcium test.
  • Strontium Levels: 5.0 – 15.0 ppm – Aim for 8 ppm.
  • Iodine Levels: – .030 to .060 ppm: Control is not recommended.

Aquarium Setup

The typical reef environment with a sand substrate is what is needed for your Burrowing Tube Anemone. A mature 50-gallon tank that is at least 9 to 12 months old is needed to provide a stable environment. The aquarium needs to be tall to accommodate the rather long tube that they form and live in. A consistently high quality water that is well oxygenated is necessary for their survival. They don’t tolerate turbulent waters, so an ozonizer is the best solution for increasing oxygen content. It must be a cold water reef, so it’s a good idea to Invest in a chiller before you obtain one of these guys. A good protein skimmer is a must.

Live rock is fine, however you don’t want so much that it takes up valuable bottom real estate. They must have a very deep fine sand substrate, just a couple inches of sand is not enough. The substrate needs to be 4 to 6″ deep to provide enough depth to accommodate their length. Hitting a bare bottom, as well as trying to burrow through course gravel (rice sized or larger), will prevent the P. fimbriatus from finding a spot to burrow and settle. This can cause them to stress and die.

A trick when you don’t have a deep enough substrate is to use a PVC tube that is 1.5 times longer than the animal. Place the animal’s tube into the pipe about 4/5’s of the way, pour fine sand around the animal, and fill to the top. Gluing a solid base at the bottom end will prevent the sand from coming out if you have to move it. Some aquarist also suggest pots, or built up areas on one side of the aquarium. Be sure their delicate tentacles are not within reach of power heads.

  • Minimum Tank Size: 50 gal (189 L) – The tank needs to be tall enough to accommodate the long tube they form and live in, and their 12″ long tentacles.
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Amount – Keep the rock from interfering with a deep sandy substrate that the anemone needs to burrow into.
  • Substrate Type: Sand – The Burrowing Tube Anemone needs mud or sand that is very fine and at least 4 to 6″ deep.
  • Lighting Needs: Low – subdued lighting – Low, actinic lighting brings out their colors.
  • Temperature: 59.0 to 68.0° F (15.0 to 20.0&deg C)
  • Specific gravity: 1.023-1.025 SG
  • Water Movement: Weak – Too much turbulence can cause them to get washed out of their tube, but the water does needs to be highly oxygenized.
  • Water Region: Bottom

Social Behaviors

The Burrowing Tube Anemone is semi-aggressive, yet as far as “anemone” type corals go, they do not have as powerful of a sting as true anemones. Several Tube Dwelling Anemone specimens can be kept in an aquarium, but they are not compatible with other anemone species. Care should be taken to provide other corals with plenty of room. Make sure when the Burrowing Tube Anemone comes out at night, their tentacles do not come in contact with delicate corals.

They are not compatible with most fish, as small fish will be stung and large fish tend to disturb the anemone. It will not host Clownfish and these fish can tear their delicate tentacles. Its only known predator is the Rainbow Nudibranch Dendronotus iris. This nudibranch never actually kills the tube anemone, it just eats and runs, leaving enough behind for the anemone to regenerate.

  • Venomous: Yes – Weak sting
  • Temperament: Semi-aggressive
  • Compatible with:
    • Same species – conspecifics: Yes
    • Anemones: Threat
    • 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 – Only cold water species that are reef safe.
    • 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: Threat
    • Snails: Safe – Only cold water species.
    • Sea Apples, Cucumbers: Threat
    • Urchins, Sand Dollars: Monitor – Only cold water species that are reef safe.
    • Nudibranch, Sea Slugs: Threat – It is preyed upon by the the Rainbow Nudibranch Dendronotus iris.
    • 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

The P. fimbriatus are hermaphrodites, meaning each specimen develops as both male and female. At a smaller size it is a male. After crossing over to a larger size/age, it will turn into a female.

Breeding / Reproduction

There is no information yet on breeding the Burrowing Tube Anemone in captivity. In the wild, the P. fimbriatus reproduce sexually with the female being larger than the male. Unlike the true anemones, they do not reproduce through asexual means such as fission, where the anemone is divided or split into parts to create a new anemone

Burrowing Tube Anemones are hermaphrodites, meaning they are both male and female. Although each animal can produce both eggs and sperm, they do not produce them at the same time, so it takes two specimens to produce a zygote. The Zygote is a fertilized egg, the beginnings of a new Burrowing Tube Anemone.

In the wild, they first release sperm and then eggs into the water column, where cross fertilization takes place. After this spawning method, the zygote will develop into planktonic larvae. It is believed the larvae live in plankton for a quite a long time, and then settle into the sand and construct a tube. How they provide brood care is not fully known, though some species have a tentacled larval stage that extends into the planktonic phase.

  • Ease of Breeding: Unknown

Ailments / Diseases

Burrowing Tube Anemones are usually hardy and problems are pretty minimal if they are provided with an adequate environment and fed regularly. There is not a lot is known about potential ailments, these anemones seem to be either alive and very well, or dead. They are very delicate and often die of starvation. Feeding them daily while maintaining good water quality is problematic.


The Burrowing Tube Anemone P. fimbriatus is easy to find in stores and online, and moderately priced. They are moderate to more expensive in price, more depending on color and size. Due to the ever changing taxonomy of these creatures, many will be listed under plain old “tube anemone.†You will need to inquire as to their origin in order to determine how to care for them properly, in terms of water temperature.


Featured Image Credit: Pachycerianthus fimbriatus by Roninacolyte, Wikimedia Commons CC SA 3.0 Unported, 2.5 Generic, 2.0 Generic, and 1.0 Generic