Gorgonian Propagation Techniques

Why Would You Want to Do It?

Some photosynthetic gorgonians have fast growth rates and have the potential to sting other corals if they brush directly against them. Hence, it may become necessary to prune gorgonians from time to time. Additionally, it's beneficial to propagate in order to spread corals in a sustainable manner, thereby reducing the draw of corals from the reef.

Get Your Tools Together

Most forms of putty epoxy work well for this project, but some are more expensive than others. Some set up particularly fast, while others may be more tacky to the touch (depending on the application, this may or may not be beneficial), and some are colored similar to coralline algae and may, therefore, blend in with your live rock more quickly than others. Regardless of the epoxy's color, though, coralline algae seems to have a propensity to grow on the surfaces of all the putty epoxies. Small pieces of live or dried base rock are useful as a mounting surface for gorgonians, and, ideally, the mounting rocks will have a small hole suitable for the insertion of part of the gorgonian. Sometimes rocks can be drilled with a masonry bit to provide this hole.

Tools for propagating gorgonians.

The gloves shown above are a protective measure. I don't consider myself as having sensitive skin, and I have no allergies that I know of; however, I have developed a serious allergic reaction to putty epoxy (a hazard of the life of a "fragger?"). I don't know if I'm allergic to only one type or all types, but I think it's likely that some of the same chemicals are used in all of the putty epoxies. Some carry warning labels about the risks of allergic reaction. I had used putty epoxy many times previously, always mixing it in my bare hands with no problems. One day, though, an hour or so after mixing it, I broke out in severely itching hives over much of my body and came very close to visiting the emergency room. So… I recommend the gloves for everyone. I usually "double glove" because the outer layer of gloves can become very sticky from the initial kneading of the uncured epoxy. Having a clean glove surface to work with (by removing one set of gloves) makes the project a little easier. Frequently wetting the gloves with some tank water also tends to make their surface less sticky to the epoxy.

Hack up the Coral

Gorgonians don't tend to ooze fluids much during the fragmentation process, so I don't think it's particularly important to remove them from a display tank when cutting out branches for propagation. The branches can simply be snipped from whatever area of the colony you like, understanding that the thin-branched gorgonians might require more cutting than you expect because branches that touch often fuse together. I usually use a scissors because gorgonians are easy to cut through, but cutting pliers or those nifty "fragging" shears can be used as well. It might also be worth mentioning that some gorgonians are very intolerant of exposure and should be kept submerged. The ones described here are not so sensitive, but seafans can be sensitive to this condition as well as the gorgonian, Muriceopsis sp. (common in the trade) and a host of others.

I regularly propagate three forms of gorgonian. The first is likely Pseudoplexaura, originally from Honduras. The left side of the photo shows the gorgonian with its polyps retracted. This gorgonian's surface becomes smooth and almost glossy in appearance with the coral's purplish tissue exposed. The right side of the photo (below) shows the same gorgonian with its polyps extended.

When this gorgonian is cut it is clear that the coral's central core or gorgonin "axis" does not have a clearly defined border.

The second gorgonian we'll be fragmenting is another thick-branched gorgonian, likely a Plexaura, obtained from the New England Aquarium in Boston. Also shown in the photo, in the lower right edge, is a tank-raised Fungia or Cycloseris, that will soon be the topic of a propagation article.

When this gorgonian is cut, its core is visible as a clearly distinct tissue. The cut for this particular fragment was made near a branch point, hence the two central cores.

This thin branching gorgonian is likely Pseudopterogorgia or Pinnigorgia. As this photo shows, this gorgonian has a clearly defined central gorgonin tissue.

Once cut, examine the base of the cutting. Some species of gorgonian have a clear demarcation of their central gorgonin tissue. Others have a more diffuse boundary within their tissues. Those with clear demarcation usually have a tough center that is almost "wood-" or "stem-like" - the gorgonin. For propagation, the tissue's outer, fleshy part needs to be scraped away. While this can easily be performed with a razor blade, care must be taken not to cut though the gorgonin. The tissue should be removed from a length of about one inch or more of the stalk.

Scraping tissue from the thick-branched gorgonian.

The clean branch, ready for mounting.

Scraping tissue from the thin-branched gorgonian.

The clean branch, ready for mounting.

It takes about a minute or two to knead the putty epoxy into a well-mixed consistency. Once the color is uniform, mixing is complete. Putty epoxy warms to some degree while it is curing. Rolling it into a ball maximizes the warming and speeds up the curing process, in case you are in a hurry. I prefer to do the initial working of the epoxy onto the rock while the putty is still soft and flows easily into small holes in the substrate. I force the epoxy into the hole in the rock, and then shape it into a small crater-like depression.

Left: Putty epoxy ready to press into the holes and crevasses in rock. Center: Forming the epoxy into a crater-like depression. Right: Epoxy ready to accept the gorgonian fragment.

I usually wait a few minutes until the putty hardens slightly before positioning the gorgonian fragment in the hole, and then shape the putty around the stalk. I have found that it's best not to embed any significant amount of the fleshy tissue under the epoxy, because any tissue that is buried will die and rot. If no fleshly tissue was removed before fragmentation, then once the tissue rots (in a few days to week) any water motion will dislodge the gorgonian fragment.

Left: Forming putty epoxy around the thick-branched gorgonian; note that no tissue is covered with putty. Right: Mounting the thin branching gorgonian.

The finished products.

After about 30-60 minutes the epoxy is sufficiently cured for the coral to be placed back into the aquarium. It's important that the fragment be returned to an area with good water flow until any damaged tissue has healed. As is the case with most soft corals, the best success rates are likely to occur if the fragmented coral is returned to a tank with conditions similar to those in which it was grown. Under good conditions, the gorgonian usually grows new tissue down onto the attachment point and hides some of the epoxy within a few weeks. The technique described above also works for sea fans that have a solid central core. Instead of putty epoxy, hot-melt glue or gel-type super glue can also be used. Pretty much any technique will work that holds the gorgonian's tissue stationary against a suitable substrate without creating undue pressure on the tissue. I've found, though, that the putty epoxy method is the most reliable way to accomplish this.

For gorgonians lacking a well-defined central core, the putty epoxy technique cannot be used because the covered tissue will rot. For these gorgonians I've found that simply strapping the gorgonian fragment onto a rock works well. I gently wrap the fragment with a few strands of monofilament fishing line, and tie it off in the back. The trick to tying knots in fishing line is to wrap one line around the other multiple times before actually making the knot. The gorgonian fragment must be held in place gently; if it is strapped down too hard, tissue damage can result and the whole fragment may succumb to microbial infection. If done properly, in several weeks new gorgonian tissue will extend onto the substrate surface. Eventually, the fishing line can be cut away and the gorgonian will sense its new orientation and begin forming new, upright branches. The disadvantage of this technique is that it may take some time for the gorgonian to look like a gorgonian again.

Immobilizing the thick-branching gorgonian that has no distinct central core; the fishing line must not be too tight or an infection may form where the coral tissue is being crushed.

Happy Fragging!

Additional Reading:

Sprung, J. 2004. Caribbean Gorgonians: Beauty in Motion. Advanced Aquarist. 3(3).

If you have any questions about this article, please visit my author forum on Reef Central.

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"Frag" of the Month - October 2006 - Gorgonian Propagation Techniques - Reefkeeping.com