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Related FAQs: Blue and Pipe Organ "Corals", "Polyps" 1, FAQs 2, Polyps 3

Related Articles: Mat/Star Polyps

/A Diversity of Aquatic Life

Two Corals That Aren't, Pipe Organ, 

Tubipora & Blue, Heliopora

Bob Fenner

Tubipora above Heliopora below

Time has seen the growth and expansion of the "marine  reef" aspect  of our hobby to include more and varied groups  of  wildlife. Amongst all the "other" stinging-celled  invertebrates  in particular,  two non-Scleractinians (the taxonomic category  that comprises the "true" or stony corals) have become stock items  in dealers and hobbyists tanks; the red pipe organ (Tubipora musica) and blue (Heliopora caerulea) "corals".

Except  for  the  ever-present  issues  of  wild-collection, natural stock depletion and reef destruction, these organisms are very appropriate in their application for captive use. They  are hardy,  easy  to maintain, and tolerant  of  aquarium  conditions relative to most true corals.

Herein is my review of what these animals are, their  placement in the scheme of other stinging-celled animal classification how to select and care for them. 

Classification: Taxonomy, Relation With Other Groups

"The  two organisms we are discussing here are  often  termed "false corals". They are members of the same phylum, the Cnidaria (Coelenterata)  or stinging-celled animals as the  "true  corals" (Order Scleractinia) and produce reef-building calcareous  skeletons,  but differ in some fundamental ways. For instance, as  you will see, these "non-coral corals" possess tentacles in  arrangements and multiples of eight, along with the sea pens, sea fans. Here is a brief view of the three living Classes of  cnidarians  ("nigh-dare-ee-ens")  largely divided on the basis  of  the predominant  physical  form their bodies take  as  juveniles  and adults, either polyp-shaped, inverted-bell (Medusoid):

Phylum Cnidaria  (Coelenterata): Stinging-celled animals.

Class Hydrozoa: simple, tube-like stomach. Small medusa stage and a small to large Polypoid stage.

Order Hydroida: Hydroids and hydromedusae, Hydra

Order Milleporina: stinging corals. Have very heavy calcareous skeletons. Millepora

Order Stylasterina: Hydrocorals; mostly deepwater.

Order Siphonophora: Typically planktonic, colonial. Physalia, the "sailor by the wind".

Order Chondrophora: Planktonic

Class Scyphozoa: Jellyfishes. Have four-chambered stomachs. Most have large medusa and small polyp stages.

Order Stauromedusae: stalked medusa.

Order Cubomedusae: Sea wasps. Medusae with four groups of tentacles.

Order Semaeostomeae: Plate-shaped medusae.

Order Rhizostomeae: Lack tentacles on the margin of the bell. Cassiopea

        Class Anthozoa: Polyp stage only, stomach divided into numerous compartments.

    Subclass Octocorallia: Octocorals. Anthozoa with eight-multiple tentacles. Almost all colonial.

Order Stolonifera: Polyps arise from a creeping mat (stolon). Skeleton of calcareous tubes. Also including: Star Polyps, Clavulariids

Includes Tubipora  (organ-pipe coral)
T. musica shown here and below.

Colonies in the Red Sea.

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.


Order Alcyonacea: Soft corals. Fleshy, rubbery. Mushroom  or variously lobate  growth  forms. Skeleton of                                                         separate calcareous spicules.                             

Order Coenothecalia: Comprised of only the Indo-Pacific  blue coral, Heliopora.                             

Order Gorgonacea: Sea fans, sea whips, precious red  jewelry  coral (Corallium).  Long  stiff internal  skeletons. Horny, upright  plantlike growth. Colonial.                             

Order Pennatulacea: Sea Pens. Colonies as fleshy, flattened  or  elongate. Anchored in  mud  or sand bottom.

And the Hexacorals:

                        Subclass Zoantharia: (Hexacorallia), Solitary or  colonial.  Eight or more tentacles, multiples of  six. Reef and reef building corals, anemones.

                               Order Actinaria: Sea anemones. Solitary or clone polyps without a skeleton. Two siphonoglyphs.

                               Order Scleractinia (Madreporaria): True or stony corals.  Solitary  or  colonial  polyps  with          calcareous skeletons.

                               Order Ceriantharia: Tube anemones, elongate tapered bodies. Live in secreted mucus tubes.

                               Order Zoanthidea: Colonial anemone-like polyps. One siphonoglyph, no skeleton.

                               Order Corallimorpharia: False corals or coral-anemones.  Solitary  or  colonial,  flattened coral-like     anemones. Tentacles   radially arranged.  Look  like true corals,  but  lack skeletons.

"The  two species of non-Scleractinian corals of interest  to us  here have almost identical criteria for selection  and  care; what is stated, unless otherwise indicated applies to both  Tubipora and Heliopora.

Heliopora coerulea Blue Coral. Here in S. Leyte 2013

Verticals (Full/Cover Page Sizes Available) Linked

The  massive colonial Heliopora caerulea is often  termed  a "living  fossil";  very  similar skeletal material  is  found  in sediments  dating  back  to the Mesozoic era,  more  than  eighty million  years  ago.  Heliopora colonies  can  appear  tree-like, plate-like or as columns depending on growing conditions;  pieces offered in the trade have been snapped off from the growing  tips of these colonies. As  far  as  appearance, blue "coral" looks  more  like  the stinging (non)coral, Millepora (actually a Hydrozoan), with  it's fine  polyps penetrating a fine crystalline matrix of  Aragonitic skeleton. Yes, their skeletons are naturally blue, throughout. /WA Corals: branching, columnar, submassive colonies • the skeleton is blue • often bright colours • azooxanthellate • member of the Octocorallia • common name is blue coral

"The  genus Tubipora has four nominal species;  though, according  to Veron,  these all probably represent only one valid  species,  T. musica.  Organ  pipe  coral is also a  massive  colonial  animal, readily  recognized  by  its blood-red  cemented  parallel  tubes interconnected  by  horizontal  platforms. As  per  the  Subclass bearing,  Tubipora  polyps have eight  tentacles,  arrayed  like feathery palms when exposed. Organ  pipe  "coral" is used extensively in jewelry  and  as ornament, and I can testify, is very often overlooked  underwater for being what it is.
/WA Corals:  massive colonies • corallum formed by a series of tubes ~ 3mm wide • polyps have eight feather-like tentacles • skeleton is bright red • can be common in the intertidal zone • member of the Alcyonacea (soft coral) • common name organ-pipe coral

Tubipora in the wild. Below in the Red Sea, open and closed and in N. Sulawesi, Indonesia.

Natural Range

Both Tubipora and Heliopora are widely distributed over  the west Pacific, to the south of Japan, west to Africa's east  coast, and up throughout the Red Sea.

Selection: General to Specific

To  some  large extent you must rely on  the  knowledge  and integrity  of your dealer in choosing these and  other  stinging-celled invertebrates. There are just too many chances for  error, notably  collateral shipping damage (delays, thermal  trauma...), that one-time simple observation cannot detect. Some guidelines:

1)  Purchase specimens that have been "hardened" for a  week or  two  at your dealers. A small deposit  should  ensure  timely holding; if not, look for another source.

2) Observe the specimen carefully at the dealers. Are polyps out and fully operational? 

3) Smell the water the animal is in; live and healthy specimens smell "earthy"; bad ones' bad.

4)  Check for necrotic, rotting "whitish" areas. Torn,  dissolving sections are indications of almost certain doom/failure.

Environmental: Conditions


Of  the  two,  Heliopora is hermatypic;  that  is,  a  reef-building  organism  physiologically  linked  with   endosymbiotic algae.  Hence its need for sufficient full-spectrum lighting  and proper placement in captive conditions. Tubipora  is much more tolerant of low-light situations  and is often found overshadowed on the reef. Just the same, it should be placed in a lighted condition.


Per a standard tropical reef captive system; steady temperature  in  the 70's, low eighties; higher pH  (upper  sevens,  low eights),  elevated  alkalinity (2.5-3), calcium  ability  (up  to 400ppm) through aragonite, other substrate, feeder, Kalkwasser... to promote calcification in these reef-building species.


Both Heliopora and Tubipora require clean, highly oxygenated water  and good current (reciprocating or not). I have seen  them maintained  in  all variations of "reef" set-ups;  with  wet-dry, natural  and induced nitrate reduction mechanisms, outside  power filtration/just  Jaubert-Monaco,  bare  tanks,  with  many  other species of "live-rock" facilitated systems...

Behavior: Territoriality

As compared with real or stony corals, Heliopora and Tubipora  are  relatively innocuous,  rarely  stinging/digesting  other contiguous  stinging  and non-stinging animals.  Take  care  that those placed near them are similarly inclined."


"Some  folks endorse "drip" acclimating these cnidarians;  in the  trade they are summarily "rinsed" in prepared  system  water and simply dunked into their respective holding systems.

Predator/Prey Relations

Coral eating fishes generally ignore blue coral, but Tubipora  can  be picked apart and is a favorite of those  nemesis'  of reef keepers, the errantiate polychaetes called bristleworms.

Reproduction, Sexual Differentiation:

Heliopora  is dioecious (separate sexes), and displays  synchronous  (at  the same approximate time) release of  gametes  in early  January. Fertilized eggs and planula larvae are  dispersed by  surface currents, settling on hard substrates  if  fortunate. Blue coral has been successfully cultured in captivity.

Feeding/Foods/Nutrition: Types, Frequency, Amount, Wastes

Some organic material in the water adds to the  survivability and  growth  of both these species.  Especially,  should  you employ  a  highly effective skimming or chemical  filtrant  unit, frequent feeding of your other livestock (fishes,  invertebrates) in their vicinity is encouraged. Additionally basting them in a dilute mash of small  animal-based food supplemented with vitamins and iodine on a daily basis (using  a low-tech plastic "turkey" baster) ensures their  nutrition.


The octocorals called blue and organ pipe are not "true"  or stony  corals,  but have found tremendous  popularity  with  reef aquarium keepers for their curiosity, beauty and hardiness. Paramount to successfully keeping Tubipora and Heliopora are plenty  of  current, sufficient  alkalinity,  calcium.  Otherwise typical  reef conditions suffice for these two non-corals,  given that you pick out initially healthy specimens.

Bibliography/Further Reading:

Allen, Gerald R. & Roger Steene. 1994. Indo-Pacific Coral Reef Field Guide. Tropical Reef Research, Singapore. 378 pp.

Barnes, Robert D. 1987. Invertebrate Zoology, 5th ed.. Saunders, USA. 893 pp.

Debelius, Helmut & Hans A. Baensch. 1994. Marine Atlas, v. 1.MERGUS, Germany. 1216 pp.

Erhardt, Harry & Horst Moosleitner. 1995. Meerwasser Atlas,  Band 2, Wirbellose Tiere. MERGUS, Germany. 736pp.

Gosliner, Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral Reef Animals of the Indo-Pacific. Sea Challengers, CA. 314 pp.

Tullock, John H. 1997. Natural Reef Aquariums. Microcosm, VT. 312

Veron, J.E.N. 1986. Corals of Australia and the Indo-Pacific. Angus and Robertson Publishers, Australia. 644pp

Weingarten, Robert A. 1992. Notes on the reproduction and development of Heliopora caerulea. FAMA 1/92.

Graphics Notes:

1-6) Heliopora in aquariums (1-3); the last a dead "curio" piece. 4-6  close up and colony shots in the wild, Cebu in  the  Philippines.

7-11)  Tubipora: 7,8 in captivity, 9 in one foot of water in  the Philippines, 10,11 in the Red Sea at about ten feet of depth.


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