Colorful Sea RodFinger Sea Fan

Red Finger Gorgonian, Yellow Finger Gorgonian
Red Finger Gorgonian Diodogorgia nodulifera, Colorful Sea Rod Picture of a Yellow Finger Coral Diodogorgia nodulifera

Red Finger Coral

Yellow Finger Coral

Diodogorgia nodulifera
Photo © Animal-World: Courtesy David Brough

The Colorful Sea Rod is an absolute beauty! But be careful, it likes cooler water and a full belly!

The Colorful Sea Rod Diodogorgia nodulifera is truly a beauty, and distinctly unique. It comes from deeper waters in areas from Southern Florida, the Caribbean and Bahamas, and down to Columbia. This coral occurs in waters deeper than 75 feet (25 meters), attached to hard-bottom substrates where there is a moderate to strong current.

Also known as the Finger Sea Fan, this is a small, sparsely branched gorgonian, occasionally rod-like. Some Diodogorgia species can grow up to 16” (41 cm) in height, however they usually only grows to about 10" (25 cm). The branches are stiff and smooth, but with such bright colors, they are easy to recognize. In fact, there are no other other gorgonians found in the Caribbean that could be mistaken for a Diodogorgia. A colony will have either red or yellow branches that are topped with contrasting calyces from which feathery polyps emerge.

The Red Finger Gorgonian is red with darker red calyces and white polyps. The Yellow Finger Gorgonian is a bright orange yellow with red calyces and white polyps. Common names they are known by include Deepwater Gorgonian, Tree Gorgonian, Finger Coral, Sea Whip, and Sea Blade. Yet the distinctive form and bright colors have led to more descriptive names like Red Finger Sea Rod, Red Finger Coral, Red Tree Gorgonian, Yellow Deepwater Gorgonian, Yellow Finger Sea Gorgonian, Yellow Tree Gorgonian, and Orange Tree Gorgonian.

The Diodogorgia genus is what you would call a “beauty with a price”. Though these gorgonians are peaceful, they are very difficult to keep alive in captivity. They are one of the most commonly offered gorgonian species, but they have a poor record of survival in captivity. The irresistible color combinations often lure aquarists into desiring a piece of the ocean, yet they are best kept by highly advanced aquarists who are willing to devote the time and resources needed for their survival.

The Colorful Sea Rod is not photosynthetic. Due to a lack of zooxanthellae (absorbing nutrients from light), they need a large amount, and steady supply of food. This can deteriorate the water quality in the aquarium, which in turn can promote algae growth. Micro algae growth along with cyanobacteria are main causes of death because they cover and suffocate the gorgonian. Keeping them in a dimly lit area of the aquarium with strong turbulent waters is helpful. Unless a specimen comes attached to a piece of hard substrate it will need to be adhered onto a rock, some suggest using underwater epoxy. The Colorful Sea Rod is rather brittle and will break, but for those who are able to keep it successfully this makes it easy to frag.

To learn more about these fascinating Octocorals see:
What Are Gorgonians? Types of Gorgonians, Sea Fans and Sea Whips


Finger Sea Fan (yellow) Diodogorgia nodulifera
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Aquarist filming their yellow Finger Sea Fan

This video makes us all want to run out and buy one of these beautiful gorgonians! Before you do, you may want to use this check list! First, your tank should be at least 50 gallons, since they can grow to 16 inches. Your tank should be at least a year old with very stable water conditions and 0 phosphates. Turn your light down or put them somewhere else in the tank that has dim lighting. When kept in a brightly lit tank, cyanobacteria seems to quickly cover and kill the Finger Sea Fan. Feed everyday with small planktonic foods or finely minced thawed frozen foods. They do not have a good record for survival, often starving or death by cyano, algae or too much handling by the aquarist.

Finger Sea Fan (Red) Diodogorgia nodulifera
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Feeding a red Finger Sea Fan

The commentary on this video is helpful. The Finger Sea Fan eats every day and uses it's white polyps to take in very small foods. They do not need much light and tend to become covered with cyanobacteria, which is hard to see on this particular color for obvious reasons. Water quality should be high and 0 phosphates. Do not buy a Flamingo Tongue snail, as it will quickly eat your beautiful gorgonian!

Finger Sea Fan - Quick Aquarium Care
  • Minimum Tank Size: 50 gal (189 L)
  • Aquarist Experience Level: Advanced
  • Temperament: Peaceful
  • Temperature: 68.0 to 75.0° F (20.0 to 23.9° C)
  • Size of organism - inches: 16.0 inches (40.64 cm)
  • Diet Type: Carnivore
  • Suitable for Nano Tank: No

Habitat: Distribution / Background

The Colorful Sea Rod Diodogorgia nodulifera was described by Hargitt and Rogers in 1901. Some other common names this species is known by are Finger Sea Fan, Deepwater Gorgonian, Tree Gorgonian, Finger Coral, Sea Whip, and Sea Blade.

They come with either red or yellow branches that have contrasting calyces, cup-like bumps on the surface, from which polyps emerge. These bright colors have led to some additional descriptive common names including Red Finger Sea Rod, Red Finger Coral, Red Tree Gorgonian, Yellow Deepwater Gorgonian, Yellow Finger Sea Gorgonian, Yellow Tree Gorgonian, and Orange Tree Gorgonian.

About the Diodogorgia Genus:

The Diodogorgia genus was described by Kuekenthal in 1919. These are soft corals in the Class Anthozoa, Subclass Octocorallia, Order Alcyonacea, and Suborder Scleraxonia. The Diodogorgia genus is further placed in the Anthothelidae family, and then under the Subfamily, Spongiodermatinae.

There are currently 3 accepted species, and they are D. capensis (Thomson, 1911), D. nodulifera (Hargitt & Rogers, 1901), and D. sibogae (Stiasny, 1941). They are not on the IUCN Red List for Endangered Species, but it is unknown if the Diodogorgia genus has been propagated in captivity.

The 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, used to show the different terpenoids or other chemicals produced by each gorgonian species.

The Diodogorgia genus are found in the Western Atlantic from Canada and south along the east coast of the United States to Southern Florida, as well as in the Caribbean, Bahamas, Puerto Rico, and Columbia. They occur at various depths, from 50 to about 500 feet (15 - 160 m) under ledges, cave walls, over hangs on walls, and other shady areas.

About the Colorful Sea Rod:

The Colorful Sea Rod is the most commonly seen gorgonian in the Diodogorgia genus. They come with either red or yellow branches that have contrasting calyces from which the polyps emerge. These bright colors have led to some additional descriptive common names including Red Finger Sea Rod, Red Finger Coral, Red Tree Gorgonian, Yellow Deepwater Gorgonian, Yellow Finger Sea Gorgonian, Yellow Tree Gorgonian, and Orange Tree Gorgonian.

They feed on small planktonic animals that rush up from deeper waters carried by currents. Their deep water habitats have low light and nutrient levels that prevents algae from growing on the gorgonian. The ocean also utilities a very strong water movement, sort of “brushing” the gorgonian constantly, and thus preventing micro algae from smothering the coral.

  • Scientific Name: Diodogorgia nodulifera
  • IUCN Red List: NE - Not Evaluated or not listed

Description

The Colorful Sea Rod usually only grows to about 25 cm (10 inches) in height, though species can grow up to 16” (41 cm). They form small, sparsely branched colonies, occasionally rod-like. They have a dichotomous structure in a random “Y” shaped branch pattern. The pattern can be quite gnarled looking. Diodogorgia species that are found growing in a fan shape are found in waters with very strong linear currents. Species with a more tree like appearance are found in very strong turbulent waters.

Colorful Sea Rod Diodogorgia Nodulifera
Yellow Finger Gorgonian
Cuba, Isla de la Juventud
Photo Wiki Commons,
Couresty Fernando Herranz Martín

The Diodogorgia genus is a member of the Suborder Scleraxonia, which are calcium based, similar to other Octocorals. They are further placed in the family Gorgoniidae. The rigid structure of branches consists 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.

The Colorful Sea Rod comes in two color forms:

  • Red Finger Gorgonian
    These specimens have deep red branches with darker red or orange raised cups, called calyces, on the surface. White to translucent polyps extend out from these cups.
     
  • Yellow Finger Gorgonian
    These specimens have orange to yellow branches. They have red or violet purple raised calyces that white to translucent polyps rise out of.

Healthy Colorful Sea Rods will have extended polyps which are often influenced by presence of food and water movement. They typically live from 1 to 1.5 years in captivity, though they will live decades in the wild.

  • Size of organism - inches: 16.0 inches (40.64 cm) - Most often reaches 10" (25 cm).
  • Lifespan: 1 years - Lives only 1 to 1.5 years in most aquariums. Lives for decades in the wild.

Difficulty of Care

The Diodogorgia genus, including the Colorful Sea Rod, are difficult to care for and have a poor record of survival in captivity. Due to their aquarium requirements and heavy dietary needs, they are best kept by advanced to expert aquarists.

These beauties live in cooler waters that are only 68 to 75˚F (20 to 24˚C), so the need for a chiller in warmer climates may be required. In order to inhibit algae and cyanobacteria growth, This gorgonian needs a moderate to strong, laminar or turbulent water flow, depending on its form. Their need for daily feeding may necessitate a set up of a continuous planktonic drip. This system can be costly and tends to foul the water. The addition of these high nutrients, though easily handled in the ocean, will quickly cause growths of micro algae or cyanobacteria in captivity. These can quickly cover and smother the gorgonian. See Care of Non-Photosynthetic Gorgonians.

Colorful Sea Rods do not like being disturbed so keep any handling to a minimum. However, lightly “brushing” the rind will often help keep them from succumbing to micro algae. The best defense is a moderate to strong, turbulent water flow and very low light. Anchor gorgonians firmly into the substrate to prevent them from whipping around the tank.

  • Aquarium Hardiness: Difficult to Impossible - Colorful Sea Rods have a poor record of survival in captivity.
  • Aquarist Experience Level: Advanced

Foods and 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, the Colorful Sea Rod does not contain the marine algae, zooxanthellae, so the need to take in food from the water column is very important to its survival.

In captivity the Colorful Sea Rod does not need light, since it has no zooxanthellae to make use of it. Because of this, they need to be fed planktonic type animals/food daily to survive. Provide feedings of Marine Snow, PhytoPlan, and other micro-plankton foods including, live baby brine shrimp, frozen thawed foods broken up into very small pieces, like copepods and other foods eaten by filter feeding corals and invertebrates. A continuous drip of live planktonic animals is expensive, yet can vital to their survival.

  • Diet Type: Carnivore - Nutrition is obtained by capturing food particles from the water column and absorbing dissolved organic matter.
  • Flake Food: No
  • Tablet / Pellet: No
  • Live foods (fishes, shrimps, worms): Most of Diet - Live planktonic prey.
  • Liquid Foods: Some of Diet - Marine snow or other phytoplankton substitutes.
  • Meaty Food: Some of Diet - Zooplankton they capture from the water column.
  • Feeding Frequency: Daily - Continuous plankton drip recommended.

Aquarium Care

Stable tank conditions are needed to keep Colorful Sea Rods and other members of the Diodogorgia genus. Water changes of 10% biweekly or 20% a month is needed, although it is suggested that doing 10% water changes once a week will replenish many of the needed additives.

With higher concentrations of coral with calcareous skeletons, there is a need to put in additional additives to maintain proper levels for good growth. The addition of iodine, calcium, strontium, and other trace elements are recommended. Phosphates should be maintained as close to zero as possible.

  • Water Changes: Weekly - 10% weekly to keep water clean.
  • Calcium Levels: 400.0 - 450.0 ppm - If using Seachem's calcium, 385 should suffice.
  • Alkalinity Levels: 8.0 - 11.0 dKH - 10 dKH is recommended.
  • Magnesium Levels: 1,200.0 - 1,350.0 ppm - Magnesium makes calcium available, so if your calcium is low, check your magnesium levels before adding any more calcium.
  • Strontium Levels: 8.0 - 10.0 ppm
  • Iodine Levels: - Dose per recommendation on label.

Aquarium Setup

The Colorful Sea Rod can reach up to 16.0 inches (40.64 cm) tall, but most often only reaches 10" (25 cm). A tank that is at least 50 gallons and 18" deep is needed to provide room for growth. A mature tank (well over a year old) is advised to increase the successful life span of Diodogorgia corals.

Quick Reference Chart
Lighting: Prefers Low Lighting Levels Prefers Medium Lighting Levels Prefers High Lighting Levels
Water Flow: Prefers Low Water Flow Levels Prefers Medium Water Flow Levels Prefers High Water Flow Levels
Temperament: Peaceful Temperament Semi-Aggressive Temperament Aggressive Temperament

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. The D. Nodulifera needs cooler aquarium temperatures 68 - 75° F (20 - 24° C), and rock work with overhangs where they can be placed.

Provide proper lighting and water movement. Any substrate is acceptable and a dimly lit environment is best. Provide enough water flow to avoid having algae and cyanobacteria to grow on them, and they must be anchored down with their roots in rubble and sand. The type of moderate to strong water movement depends on the shape of the gorgonian. If it is a flat fan shape, then the water should be laminar and moderately strong. A typical gnarled tree shaped full specimen will need moderate to turbulent water.

  • Minimum Tank Size: 50 gal (189 L) - A 50 gallon tank or larger that's at least 18" tall.
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Amount - Form ledges and overhangs to put them under.
  • Substrate Type: Any
  • Lighting Needs: Low - subdued lighting - Dim lighting is needed for the Colorful Sea Rod.
  • Temperature: 68.0 to 75.0° F (20.0 to 23.9° C)
  • Specific gravity: 1.023-1.025 SG
  • Water Movement: Moderate - Fan shaped specimens need moderate to Strong, laminar flow. Tree shaped specimens need moderate to strong and turbulent.
  • Water Region: Bottom - Anchor them firmly in rubble and sand.

Social Behaviors

The Colorful Sea Rod is very peaceful, and it poses no threat to any other corals or gorgonians. This gorgonian should be kept with other "no/low light" corals that need constant feeding and a good water flow. Their low light need is not conducive to survival of many other corals. The stronger currents that the Finger Sea Fan needs are typically too much for other corals, as well, and can stress them out and cause their demise.

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. Avoid the Flamingo Tongue snail which is readily available for purchase since it will eat your gorgonian, and also avoid snails from the Murex genus.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species - conspecifics: Yes
    • Anemones: - They will not survive in the strong currents, low light, and high nutrient environment of this gorgonian.
    • Mushroom Anemones - Corallimorphs: Threat - They will not survive in the strong currents, low light, and high nutrient environment of this gorgonian.
    • Leather Corals: Threat - They will not survive in the strong currents, low light, and high nutrient environment of this gorgonian.
    • Zoanthids - Button Polyps, Sea Mats: Threat - They will not survive in the strong currents, low light, and high nutrient environment of this gorgonian.
    • Sponges, Tunicates: Safe
    • Starfish: Monitor - Delicate species will not do well in the high nutrient environment of this gorgonian.
    • Feather Dusters, Bristle Worms, Flatworms: Safe
    • Clams, Scallops, Oysters: Threat - They will not survive in the stronger currents, low light, and high nutrient environment of this gorgonian.
    • Crabs: Threat
    • Snails: Monitor - While most snails are safe, Murex genus snails and Flamingo Tongue snails will eat them.
    • Sea Apples, Cucumbers: Threat
    • Urchins, Sand Dollars: Threat - Delicate species will not do well in the high nutrient environment of this gorgonian.
    • Nudibranch, Sea Slugs: Threat - Delicate species will not do well in the high nutrient environment of this gorgonian.
    • Copepods, Amphipods, Mini Brittle Stars: Monitor - All are safe, however there are a few predatory copepods that should be removed before placing the gorgonian in the system.
    • Stony Corals: Threat - is aggressive - They will not survive in the strong currents, low light, and high nutrient environment of this gorgonian.
    • Soft Corals: Threat - is aggressive - They will not survive in the strong currents, low light, and high nutrient environment of this gorgonian.

Sex: Sexual differences

There are no discernible sexual differences.

Breeding / Reproduction

The Colorful Sea Rod can reproduce by breakage, fragmentation. The may also spawn like other gorgonians for sexual reproduction. When ready to spawn, the Diodogorgia genus will release mature gametes into their digestive system, which is then released up and out through the mouth. After this spawning method, the zygote will develop into planktonic larvae or free floating in open waters. They will form tentacles, septa and a pharynx right before they settle into the reef with the mouth pointing upward.

It is yet unknown if any of the Diodogorgia genus has been successfully propagated in captivity. However, they are rather brittle and will break. so for those who are able to keep it successfully this makes it easy to frag. 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.

  • Ease of Breeding: Difficult

Ailments / Diseases

The Colorful Sea Rod, as well as the entire Diodogorgia genus, is very susceptible to being smothered by micro algae and cyanobacteria, even in dimly lit tanks. If they are exposed to light, which will not harm or help them, they can also get red band and black band infections that are also caused by cyanobacteria. Keeping a stronger water flow and gently regularly “brushing” their rind 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. Freshwater dips can also kill cyanobacteria, and are an effective treatment.

  • Black Band Disease (BBD)
    This ailment is characterized by a leading band of black gooey material (mostly algae), which leaves a denuded skeleton behind. The bare skeleton then becomes covered with many species of algae. You can use a needle to lift the black band from the coral skeleton. With a small diameter airline tubing, siphon the black front away, catching any loosened debris as well. If it is not possible to remove all of the black band, you may be able to treat the area directly by applying a small amount of Erythromycin or Chloramphenicol.
     
  • Red Band Disease (RBD)
    As the name "red band" indicates, this ailment is characterized by a brick red or dark brown band. The band is a soft microbial mat which will easily dislodge from the surface of the coral.

They must also be fed on a regular and ongoing basis or will not survive in the aquarium. The second highest mortality for the Diodogorgia genus is starvation. They may have open polyps but can slowly starve over the next 12 to 18 months. Diodogorgia species may also be a food source for Flamingo Tongue Snails Cyphoma spp. and snails from the the Murex genus.

Availability

The Colorful Sea Rod, also called the Red Finger Gorgonian and Yellow Finger Gorgonian in the hobby, are easy to find at pet shops and online. They are moderately expensive, but prices vary depending on size and color.

References

Author: Clarice Brough CRS, Carrie McBirney
Lastest Animal Stories on Finger Sea Fan