Propagation of Colt and Organ Pipe Corals

Propagating Colt or Klyxum Genus Corals

Colt or Klyxum corals (previously described in the literature as Cladiella) are extremely soft and somewhat slimy to the touch. Colt coral is prone to microbial infections during propagation efforts. Sections of coral can be cut with a razor blade or scissors and can be placed into small cups partially filled with gravel or small rocks. The cups have to be covered sufficiently with some type of plastic netting, or placed in an area with low current so that the cuttings do not become dislodged. It can take several weeks or more for colt cuttings to attach sufficiently to the gravel before they can be handled again. Once they have reached this point, the gravel pieces attached to the coral can be dried with a paper towel, and gel type cyanoacrylate glue can be used to attach them to a large rock in a manner similar to that described in last month's article on propagation of small-polyped stony corals. Unfortunately, colt corals propagated in this manner still sometimes detach and blow away in the current. Also, the low flow conditions necessary in the gravel cup to allow the coral to attach to the gravel are very conducive to microbial growth on the damaged tissue, which can turn the coral into a pile of mush in a matter of days.

Though somewhat time consuming, another propagation method that I have tried with colt corals is the "sewing" method. The coral's tissue is pierced in multiple locations and then very gently tied onto a substrate using thin fishing line or nylon thread. Unfortunately, colt corals have a tendency to pull away from any materials that are imbedded in their tissue, and often pull away from the thread before they can successfully attach to the substrate. This method can work with some corals that have a high density of sclerites (small calcium carbonate skeletal elements that help a soft coral maintain its shape) in their tissues, such as those covered in a previous propagation article, but rarely works on a coral with low densities of sclerites, such as colt corals.

I've largely abandoned the "cup" and "sewing" methods for colt coral propagation, as I've found them far too time consuming and prone to failure. Instead, I use a sharp razor blade to cut a lobe of the coral down to the base rock to which it is attached. I then cut the coral completely free from the main rock by cutting through the rock using a high-speed rotary tool with a diamond cutoff wheel. For most coral or calcium carbonate based rocks, this should not be difficult to do. If the fragment with its small, attached rock is heavy enough to maintain a stationary position in your tank's current, the fragment can immediately be placed back into the tank and allowed to heal. Alternatively, the fragment can be secured to a larger rock with cyanoacrylate glue, or putty epoxy (see this article for proper use and precautions for using putty epoxy). I usually try to choose a rock substrate that is soft, porous and easy to cut though. That way, in the future, when the small fragment is again a large colony, the fragmentation process will go smoothly. If the piece of rock still attached to the coral is small enough, you might be able to drop or glue it into a hole bored into a rock. Such a hole would need to be large enough so that, initially, the coral can receive good water motion around the areas that need to heal. Eventually, the coral's tissue will grow sufficiently to attach to all sides of the hole, and can be propagated again. Once a fragment is cut free from the main rock great care must be taken to handle it as little as possible. Colt corals tend to pull away and detach from whatever substrate they are on if they are handled excessively. Using the method just described I've successfully fragmented a single colt coral into seven separate colonies in one session.

Propagation of Organ Pipe or Tubipora Genus Corals

Tubipora musica, or organ pipe corals, are relatively easy to propagate. I've found that the best method consists of just cutting the coral into pieces using a serrated knife or a hacksaw blade. Their skeleton is extremely soft and easy to cut. Once the coral is cut into sections, a flat area can be ground on its base with a high-speed rotary tool with a diamond cutoff blade. The base can then be dried and glued to a small rock or concrete disk using cyanoacrylate glue. The coral will continue to grow and, in some cases, to secrete skeleton that will attach it naturally to the substrate. Alternatively, if the coral is large enough, it may not be necessary to secure it to any substrate at all. Tubipora that are collected from the wild may have large densities of sponge growing all though their skeleton's base. If propagation efforts are attempted on a wild-collected Tubipora, it might be a good idea to minimize the coral's exposure to air. Some sponges exposed to air start to die, which might also promote microbial infections in the coral itself. As long as no glue is involved, there is no reason the entire fragmentation process cannot be performed under water. For corals that have been grown mostly in a reef tank environment, I've not found the minor growth of sponge within the coral's tissues to be a problem during propagation.

Underwater putty epoxy can also be used to secure the cut pieces of Tubipora. Unfortunately, Tubipora's skeleton is so soft that it often gets crushed when the putty epoxy is formed around its base.

Happy fragging!

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