Finger Sea FanColorful Sea Rod, Finger Coral
Red Finger Coral
Yellow Finger Coral
|Photo © Animal-World: Courtesy David Brough|
The Finger Sea Fan is quite common due to its absolute beauty! But be careful, it likes cooler water and a full belly!
The Colorful Sea Rod or Finger Sea Fan Diodogorgia nodulifera is truly a beauty, and distinctly unique. They come from deeper waters in areas from Southern Florida through the Caribbean and Bahamas, and down to Columbia. These corals are usually found in water deeper than 25 meters (75 feet) on hard-bottoms. They are attached to the bottom in moderate to strong currents.
The Finger Corals form small, sparsely branched colonies. The Colorful Sea Rod or Finger Sea Fan comes in two colors. The Red Finger Gorgonian or Red Finger Coral is red with darker red calyces and white polyps. The Yellow Finger Gorgonian is a bright orange yellow with red calyces and white polyps. Some common names they are known for are the Colorful Sea Rod, Deepwater Gorgonian, Finger Coral, and Finger Sea Fan. Yet the distinctive form and bright colors have led to more descriptive names, with the color then inserted. Some of these are Red Finger Sea Rod, Yellow Finger Sea Gorgonian, (insert color) Tree Gorgonian, Sea Whip, Sea Blade, and Tree Gorgonian.
The Diodogorgia genus is what you would call a "beauty with a price". Though Finger Gorgonians are peaceful, they are very difficult to keep alive in captivity. They are not photosynthetic. Due to a lack of zooxanthellae, there is a need for a steady food supply to keep them alive with several feedings a day being optimal. They are also prone to succombing to microalgae. Keeping them in a dimly lit area of the aquarium with strong turbulent waters is helpful. See Care of Non-Photosynthetic Gorgonians.
Some Diodogorgia species can grow up to 16" (41 cm) in height, however the Finger Sea Fan usually only grows to about 25 cm (10 inches). Unless it comes attached to a rock it will need to be adhered onto a rock, some suggest using underwater epoxy. Finger corals are rather brittle and will break, but for those who are able to keep them successfully this makes them easy to frag. These Gorgonians are best left fo highly advanced aquarists who are willing to devote the time and resources needed for its survival.
To learn more about these fascinating Octocorals see:
What Are Gorgonians?
Types of Gorgonians, Sea Fans and Sea Whips
Distribution / Background Gorgonian Information: The Diodogorgia genus was described by Kukenthal in 1919. There are 7 species, and they are D. capensis, D. ceratosa, D. cervicornis, D. crustata, D. laauense, D. nodulifera, and D. sibogae. It is unknown if the Diodogorgia genus has been propagated in captivity.
The Colorful Sea Rod or Finger Sea Fan D. Nodulifera is the most commonly seen gorgonian in this genus. This gorgonian was described by Hargitt in 1901. Some common names they are known for are the Colorful Sea Rod, Deepwater Gorgonian, Finger Coral, and Finger Sea Fan. Yet the distinctive form and bright colors have led to more descriptive names, with the color then inserted. Some of these are Red Finger Sea Rod, Yellow Finger Sea Gorgonian, (insert color) Tree Gorgonian, Sea Whip, Sea Blade, and Tree Gorgonian.
Where Diodogorgia Corals Are Found: The Diodogorgia genus are found in the Caribbean, Bahamas, Southern Florida, Puerto Rico, and Columbia.
Diodogorgia Coral Habitat: The Diodogorgia genus are found under ledges, cave walls, over hangs on walls, and other shady areas. They can be found in various depths, from 50 to about 500 feet (15 - 160 m). These deeper waters have a lower light and lower nutrient level that prevents algae from growing on this gorgonian.
Description What do Diodogorgia Corals look like: The Diodogorgia genus form small, sparsely branched colonies. They have a dichotomous structure which is a random "Y" shaped branch pattern. The pattern can be quite gnarled looking. They have a rigid structure of branches that consist of a protein substance called gorgonin. There is a central axis that is the main branch from which the rest of the coral grows. The structure is covered by a tissue layer called a rind, with the polyps on raised areas, or bumps on the rind. Some Diodogorgia species can grow up to 16" (41 cm) in height.
The Colorful Sea Rod or Finger Sea Fan D. nodulifera usually only grows to about 25 cm (10 inches). It comes in two color forms:
- Red Finger Gorgonian is a deep red. It has darker red or orange raised cups called calyces that white to transluscent polyps rise out of.
- Yellow Finger Gorgonian has orange to yellow branches. its has red or violet purple raised, cups called calyces, that the polyps rise out of.
Classification of gorgonians in general is done by some simple visual clues such as colony size, shape, axis structure, color, polyp placement, and pattern of branches. Getting a little more technical, they also look to see if the polyp is autozooid or siphonozooid. Then there is the more exacting use of chemotaxonomy. This is being used to show the different terpenoids or other chemicals produced by each gorgonian species.
Difficulty of Care Gorgonian Care: The Diodogorgia genus is difficult to care for due to their heavy dietary needs. They are also prone to succombing to microalgae. They need enough water flow to avoid having algae and cyanobacteria grow on them, and must be anchored down so the water doesn't send them whipping around the tank. They do not like being disturbed so keep any handling to a minimum.
Foods / Feeding Gorgonian Feeding: In the wild, Diodogorgia corals have developed several feeding strategies. They capture planktonic organisms and microscopic food particles from the water column, and can absorb dissolved organic matter. Unlike other Octocorals, most of the Diodogorgia sp. do not contain the marine algae, zooxanthellae, so the need to take in food from the water column is very important to their survival.
In captivity the Finger Sea Fans do not need light, since they have no zooxanthellae. But in general the Diodogorgia corals do need to be fed plankton type foods daily to survive. Provide feedings of micro-plankton, live baby brine shrimp, or other foods designed for filter feeding corals and invertebrates.
Aquarium Care Stable tank conditions are needed to keep the Diodogorgia genus. Doing water changes of 20% a month or 10% biweekly is needed, although it is suggested that doing 5% water changes once a week will replenish many of the needed additives. The addition of iodine, calcium, strontium, and other trace elements are recommended.
Suggested levels for Diodogorgia species are:
- Calcium: 400 - 450 ppm
- Alkalinity: 3.2 - 4.8 MEQ/L (8 to 11 dKh - 10 is recommended)
- Phosphates: 0, zero.
- Magnesium: 1200 - 1350 ppm.
- Strontium: 8 - 10
|Quick Reference Chart|
A typical live rock/reef environment is what is needed for your Colorful Sea Rod or Finger Sea Fan, along with some fish for organic matter production. A mature tank (well over a year old) is advised to increase the successful keeping of Diodogorgia. The D. Nodulifera needs cooler aquarium temperatures, and rock work with overhangs where they can be placed.
Provide proper lighting and water movement. A dimly lit area of the tank is required for Colorful Sea Rod or Finger Sea Fan to do well. Provide enough water flow to avoid having algae and cyanobacteria to grow on them, and they must be anchored down. These Octocorals are not an aggressive species. They get along well with their own kind and pose no threat to any other corals.
- Minimum Tank Size / Length: 50 gallon (190 L) or larger
- Marine Lighting: Low, dim
- Temperature: 68° - 75° F (20° - 24° C)
- Salinity / Specific Gravity: 1.023 - 1.025
- Water Movement: Moderate, turbulent
- Water Region: Bottom of the aquarium
Compatibility and Social Behaviors The Diodogorgia genus is peaceful, and they pose no threat to any other corals or gorgonians. Butterflyfish feed on gorgonian polyps or tissue. Butterfly fish will constantly chow, so they are not the best idea for a tank mate. Some angelfish will also pick at the polyps, but can be housed with them if the angelfish is well fed.
Propagation of gorgonians consists of using severing or clean cuts. Tearing the coral will result in infection. Be cautious with the use of glues, as many gorgonians react badly to the chemicals. However an underwater epoxy has been suggested by some. Containment is recommended if the frag survives. This involves keeping the frag in one spot, say a small piece of upright pvc, around the same height as the frag, with sand or rubble at the bottom. This will keep the frag from blowing over before it can take root. It is suggested to drill holes in the pvc to keep the water flowing.
Potential Problems The Diodogorgia genus can get red band and black band infections that are caused by cyanobacteria. Keeping water flow strong will help prevent this. If your gorgonian does get this, you can at times cut off the bad part and hope the rest will recover. They must also be fed on a regular and ongoing basis or will not survive in the aquarium.
Availability Gorgonians for Sale: The Colorful Sea Rod or Finger Sea Fan D. Nodulifera are easy to find at pet shops and on line. Online they can run about $30.00 USD or more, depending on size and color.
- Animal-World References: Marine and Reef
- Eric Borneman, Aquarium Corals : Selection, Husbandry, and Natural History , TFH Publications, 2001
- Anthony Calfo, Book of Coral Propagation, Volume 1 Edition 2: Reef Gardening for Aquarists, Reading Trees; 2nd edition, 2007
- Harry Erhardt and Horst Moosleitner, Marine Atlas Volume 2, Invertebrates (Baensch Marine Atlas), Mergus Verlag GmbH, Revised edition, 2005
- Bob Goemans, Orange/Red/Yellow Tree Gorgonian, Diodogorgia nodulifera, Animal Library, Saltwatercorner.com