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Related FAQs: Sea FansSea Fans 2Gorgonian, Sea Fan Identification 1, Sea Fan ID 2, Sea Fan ID 3, Sea Fan ID 4, Sea Fan BehaviorSea Fan Compatibility, Sea Fan Selection, Sea Fan Systems, Sea Fan Feeding, Sea Fan Disease, Sea Fan Reproduction,

Related Articles: Octocorals, Water Flow, How Much is Enough

/The Conscientious Marine Aquarist

Sea Fans for Marine Aquaria, the Gorgonians, Order Gorgonaceae

Part 1

To: Part 2, Part 3, Part 4, Part 5, Part 6

Bob Fenner

Gorgonian Sea Fan, Fiji

What the deuces are sea fans anyway? Those scraggly stick things you see in fish stores or hanging on the wall at The Seafood Restaurant? Well, sort of; those are actually only the vestiges (skeletons) of what were sea fans. Looking at a human skeleton, have you ever heard, "What a babe/hunk!"; probably not. If you think sea fans are attractive as dead remnants "you ain't seen nothing yet".

Most everyone has seen sea fans on the boob tube; even had a sea fan in their hand, Order Gorgonacea, as a skeleton turned into a piece of jewelry. If you've been diving in tropical seas, you've brushed by them "waving" in the current.

Verticals (Full/Cover Page Sizes Available

Can they be kept in captivity? Yes. There is a much stultified place/market for these octocorallians in the schema of marine aquaria. Like many saltwater invertebrate groups, sea fans have been kept on the side lines thus far for simple, correctable reasons/problems.


Sea fans and their relatives are members of the Phylum Cnidaria (Coelenterata) and therefore possess specialized stinging cells and sticking cells, no organs, "bag in a bag" body structures. Evolutionarily they were the first group to have a gastrovascular cavity; allowing them to take advantage of larger prey (up from the simpler sponges).

Like the previous coral, tube and "true" anemone groups, the sea fans are members of the Class Anthozoa. In contrast with the other Cnidarian classes (Hydrozoa, Scyphozoa) that have medusa body plans (inverted bells with either a simple body tube or one divided into four areas), the polypoid Anthozoans bodies' are divided into numerous chambers by septa (partitions).

If you want, refer back to the systematic overview of the stinging-celled animals, Section 4) A) ii) b) for a clearer picture of how this group is further placed. The Class Anthozoa is comprised of two Subclasses. The anemones in Subclass Zoantharia have polyps with more than eight tentacles, typically in cycles of twelve. Our sea fans are in the Subclass Octocorallia (or Alcyonaria) have polyps with eight pinnate tentacles. Almost all of them are colonial.

Octocorallians include the soft corals, that lack stiff skeletons, Order Alcyonacea; and other non- "true corals" such as the Pacific blue coral, Heliopora (Order Helioporacea); the organ pipe coral, Tubipora (Order Stolonifera); and more. These don't possess the calcium carbonate skeletons of "true" stony corals (Subclass Zoantharia, Order Scleractinia), though they do have scattered CaCO3 spicules.

Sea fans, Order Gorgonacea, are colonial Anthozoans anchored on hard substrates, supported by an internal, central horny/wood-like skeleton. They're colonies are covered by a thick "rind-like" skin. Unlike anemones, but like corals, sea fan polyps are interconnected by an internal germ layer (gastrodermis) and mesoglea. This feature explains much regarding how one part can feed and sustain the rest of the colony, and unfortunately how disease can easily spread.

Common genera include Gorgonia, the purple sea fan from Florida/Caribbean, the dried "ornamental" fan skeletons in stores. Corallium is the beautiful red sea fan used in jewelry. Paragorgia, Pterogorgia, and Pseudopterogorgia; and others are often encountered, offered for aquarium use.

Gorgonians are found worldwide in tropical seas. They are prominent of most reefs, attached to rocks, corals, oriented to prevailing currents.

Gorgonian Species on Parade!

Acabaria splendens, Splendid Knotted Fan Coral. Deeper water species that is planktivorous. Gorgeous close-ups showing the flexible "knots" at the anastomoses of a colony. Red Sea pix. 

Acalycigorgia sp. Many prominent calyces. Not totally retractable, often bright warm-colored, contrasting with rind/cover... Western Pacific. N. Sulawesi pic. 

Family Briareidae

Briareum sp. Blainville 1830. Briareum Soft Coral. Family Briareidae. Colonies to 10 cm. N. Sulawesi (Lembah Strait) pic. These are encrusting species with off white tentacles and bright white centers. Easily cultured in established tanks with strong current and intense indirect lighting. Important to isolate from stony and soft corals as these gorgonians can overgrow and smother them. 

Briareum asbestinum, Corky Sea Finger, Deadman's Fingers. Colonies made up of one or more erect cylindrical columns, with large "hairy" polyps, occasionally encrusting. Rods purple to gray in color, polyps lighter. Images below: An upright colony in the Bahamas and a more encrusting form in Tobago. Colored purplish rind of encrusting colony in Bahamas and close-up by Di in Cozumel.
Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Genus Ctenocella:

Ctenocella pectinata (Pallas 1766). Characterized by distinctive parallel branches arising from a Y-shaped base. Thailand, Indonesia, Australia. This one off of Pulau Redang, Malaysia in sixty feet of water. 

Genus Diodogorgia:

Diodogorgia nodulifera, Colorful Sea Rod. Occurs as branched and rod forms. Polyps  in cone-shaped calyces on red to orange rinds/stalks. Polyps white. Bahamas and Tobago pix. 

To: Part 2, Part 3, Part 4, Part 5, Part 6

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