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/The Conscientious Marine Aquarist

Sea Fans for Marine Aquaria, the Gorgonians, Order Gorgonaceae

Part 1

To: Part 2

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. 

Genus Erythropodium:

Erythropodium caribaeorum, Encrusting Gorgonian. Form encrusting mats that look hairy when polyps are extended, smooth, light colored, like leather when retracted. 

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 Eunicea:

Eunicea calyculata, Ellis & Solander 1786, the Warty Eunicea. Key West 2014

Eunicea mammosa, the Swollen-Knob Candelabrum. Tropical West Atlantic. To about a foot in height. Closely packed tubular calyces. Candelabrum like in appearance overall. Have tube-like calyces and candelabra-like colonies. Most are light gold in color. Exist in many types of reef environments. High to low light, water movement. Di pix in Cozumel. Below: Aquarium and Cozumel images. 

Verticals (Full/Cover Page Sizes Available

Genus Gorgonia:

Gorgonia flabellum, the Venus Sea Fan. Large fans of one plane whose branches are interlaced and roundish to squared off at angles to the fans surface in profile; i.e. have non-unifacial elements. Below: Bahamas, Belize close ups and big colony.
Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Gorgonia mariae,  Sea Fan. Cozumel 2014

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

Gorgonia ventilana, the Common Sea Fan. Similar to the Venus Sea Fan (above), but with branches that are flattened in profile, not roundish. A close up of the skeleton of G. ventilana on the left, B. flabellum on right in the Bahamas. Both mainly purple, but varying to whites, yellows, as second close up (Bahamas) shows. 

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

Cautious Success with Guaiagorgia sp.    10/14/13
Good Afternoon Crew,
Thanks for all you do. In the last 7 years I have grown in skill and understanding through WWM and would like to share some success with a Blueberry Gorgonian.
The specimen I purchased from the LFS here in San Diego was a vibrant, healthy looking specimen in a typical sea fan spread. The polyps were open at the store, and have been regularly here in my 75 gallon square tank the past three months.
The Gorg is placed mid-way down in my tank (30"x30"x18") about 16"  on center form  a Vortech MP40 running at 35% on "Tidal Swell". I have two MP40s on the back, each running at relatively low volume and anti-syncing.
The "Lagoon" program is used overnight.
In looking at the morphology of my specimen it was obvious that most of the polyps faced one direction, perpendicular to the fan. Based on the limited success of many reef keepers I decided NOT to follow the norm and pointed the polyps away from direction of water flow. I think this is a key element in my success.
<I agree>
All new growth to date (estimated 15%), both on the tips of the branches and on the "truck" near the base, have been away from the current. It seems to follow that although this specimen requires a brisk current to keep the branches free of debris, the mouths generally can only catch food in the more tranquil direction. If the specimen is oriented "backwards" from the start, feeding may be impossible.
The polyps are always open in the evenings... and most days, but can be enticed easily if closed with a small amount of Cyclop-eeze in the water.
Currently I am feeding Hikura Daphnia w/ Cyclop-eeze w/ H20 Life Marine Fusion. The new polyps are very, very small, so the "shotgun" approach to different feed sizes are an attempt to satisfy all, It appears to be working.
This is a mature tank, with ample copepod production to satisfy two Mandarins without supplemental feeding. I believe this fact plays an important role as well, especially for the smallest polyps.
<I concur here as well>
During feeding, I slow the Vortechs to 15% on Reef Crest. This is just enough to keep water moving randomly and let the "missed" food recirculate.
I use a large baster to target feed, but only trickle the food out and gently push it through the fan. In my experience these polyps will close up at from direct "blasts". This is easy to see when you use an empty baster.
I practiced feeding "empty" a few times to see how much flow the polyps could handle and still grab the food. It is not much!
I feed twice a day, religiously.
I hope these notes further the cause. I am "tech heavy" so an equipment list and parameters follow...
30"x30"x18" tank
24 gallon refugium /Chaeto (reverse lighting cycle)
3" DSB (med grain)
110lbs live rock
Apex Controller
pH x 2, ORP, Temp x 2, probes
Dual Ecoxotic Canons
Karollin 1502 Calcium Reactor
Overnight Kalk drip (to counteract the CO2).
Precision Marine Skimmer (runs 24/7)
Temp: 76.9 - 77.5
pH: 8.00 - 8.18
SG: 1.026
ORP: 310 - 330 (day/night)
Nitrates: 0
Calcium: 420ppm
Magnesium: 1260ppm
Alk/DKH: 9.3
Lights: 12hrs (inclusive of 150 min ramp time at each end)
Lunar: Apex module
<Thank you for sharing! Bob Fenner>
Re: Cautious Success with Guaiagorgia sp. 11/8/2013

Good afternoon Crew... after an additional month of observations an update on my Blueberry Gorg.
<Hey Steve>
As other reef keepers have experienced over time, my polyps started to extend less often, and for shorter duration. Water parameters have remained consistent, as well as feeding frequency and variety. So I started examining the effects of light intensity,
My first observation was that the polyps that were furthest from my light source (dual Ecoxotic canons) seemed to open sooner and longer that the polyps closer to the light source. Knowing that this species comes from a range down to about 75 feet or so, and often on sloped reefs,  I decided to shield the Gorg to create an imbalance in the lighting, skewing it towards
the 460nm range.
Initially, I put a third of the specimen in complete shade with two thirds exposed to the 460nm cannon (I blocked the10,000k). This initial step yielded an immediate improvement. After a week, the third that resided in total shade started to open regularly but not with the same vigor as the 460nm portion which was back to "normal". I have since placed the entire Gorg under the 460nm (again, no 10k) and the growth and polyp extension has resumed. Polyps are now open appx. 20 hours per day.
So in sum, here are my novice observations;
  - Have a mature, copepod producing tank.
  - Place is a diffused, moderately strong, random current.
  - Face the polyps away from the primary direction of flow.
  - Effect reversing tidal flow if possible.
  - Feed a large variety of food sizes.
  - Let the food float into the polyps, don't blast with a pipette.
  - Beware of even moderate, 10k+ lighting sources.

I feel fortunate that my light sources are so narrow, it makes the shielding fairly simple. I can see how in standard lighting systems with 48" T5s let's say, it would be difficult to create the right conditions.
<Yes; I would insert my usual statement here that most systems are overlit, too intense and too long duration; compared with naturally occurring parameters>
Often I've read how keeper's Gorgs stop opening and a quest for a "more enticing" food ensues. What I believe now is that the deterioration is due to the physical environment, and the Gorg's inability to adapt to typical tank lighting. More light... more stress...no polyp extension... no food...and the death spiral starts.
Temp: 76.9 - 77.5
pH: 8.00 - 8.18
SG: 1.026
ORP: 310 - 330 (day/night)
Nitrates: 0
Calcium: 420ppm
Magnesium: 1260ppm
Alk/DKH: 9.3
Lights: 12hrs (inclusive of 150 min ramp time at each end)
Lunar: Apex module
Happy reefing!
<I thank you again for sharing. Will update/addend your prev. post. Bob Fenner>
Re: Cautious Success with Guaiagorgia sp.   12/26/13

Closing in on 6 months with the Blueberry Gorg and we are thriving here in Southern California!
<Great news!>
This winter's calendar included a two week trip out of the country and my "fish tender" failed me at the last minute. So the Gorg (and other species) had to survive on just a couple of frozen food cubes every few days provided by my brother.
With no target feeding and a lack of personal attention, I resigned myself finding a decaying Gorg upon return... Ugh. Happily, although initially a bit unhappy with semi-closed polyps, the Gorg began to open as usual within 24 hours and feeding/growth continues.
The more I observe this species the more I'm convinced that failure to maintain health is due to the physical parameters of their environment and the maturity of the tank. Now that the lighting and current is dialed in, I am only target feeding a few days a week using ova, Coral Fusion and Cyclop-eeze. There are some sections of the fan that receive no target feeding at all (blocked pipette access) and they continue to thrive.
So my recommendation continues to be for those with Blueberry issues... stop focusing solely on the types of food. Reduce your lighting, create moderate random flow, and regular (daily not required) target feedings. A mature tank is a must!
Happy Reefing!
<Thank you Steve. Bob Fenner>

Ongoing Blueberry Gorg Success - Update     2/21/14
Good Evening Bob,
<Steve... your files... are an order of magnitude too large for our mail server. Please>
Things continue to go well here in San Diego!
<Ah yes... I live in Mira Mesa>
Thought I would share a couple of pictures about 8 months along. I estimate about 25% growth at this point, approximately 7" in diameter.
[image: Inline image 1]
These types of polyps, with the longer tentacles, typically form in high flow areas...
[image: Inline image 2]
Thanks again for helping us with this truly fascinating hobby!
<Thank you for sharing.... just smaller pic files going forward! BobF>

Appears to be a Hydrozoan at the yellow pointer
Isis hippuris Linnaeus 1758, the Golden Sea Fan. Indo-Pacific; Red Sea, Australia, Indonesia, Sri Lanka. To about sixteen inches tall. Needs good current, daily feedings, low lighting (no metal halides) for captive care. Golden in color when polyps are extended. Closed and open colonies off the Whitsunday's, Queensland, Australia. 

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