There was a time not too long ago when the very idea of keeping living corals and other sessile invertebrate successfully in captivity seemed an almost certain impossibility. What would even the most advanced aquarist have thought if they could have taken a look through a magic window and seen what we are accomplishing today?
Not only are we maintaining corals once thought impossible to sustain in captivity, we are turning out results which sometimes surpass even those found in nature! Not only are our organisms surviving, they are thriving and to the point where we are aiming at someday helping to replenish the levels in the ocean itself!
To obtain this long-term goal, we must understand our organisms and share information with one-another for every reef-keeper has the potential to make a solid impression on this goal.
Understanding our organisms reproductive processes is paramount to reaching this goal and learning to successfully propagate coral specimens is a big step in that direction.
The tools used to propagate corals are many and new techniques are being discovered on a routine basis. A good propagating tool-box may include such items as:
Exacto-knives or other razor blades
Small hammer and chisel
Hacksaws or electric saws
Dental Floss or other medical-grade strings
Super Glue or other fast-setting gels
Long Stainless-steel forceps
These are just a few of the commonly used tools one might find useful when propagating corals, though many more exist. Finding what works best for you is the key.
Methods used to propagate corals are almost as varied as the many tools used. Every type of coral has its preferred methods for propagation, from slowly drawing two sections apart over the period of a couple of weeks, to lobbing off sections as if you were cutting a carrot. Attaching these newly propagated corals is also just as varied and creates a challenge all of its own.
Assisted a-sexual reproduction is the method of dividing a coral into two or more pieces utilizing different methods. Each new colony that results from such division is essentially an identical clone of the parent colony.
SLOW CONSTRICTION: This method utilizes a thin string or other material to slowly cut through a section of coral, usually over an extended period lasting a week or longer. It is a very safe method that is used mostly on soft corals, though a very labor intensive method.
CUTTING: This method utilizes sharp shears, a razor-blade, or other sharp tool to cut through coral tissue. It is a quick method for propagating corals though also normally only used for soft corals.
SAWING: Branchy hard corals are too hard to cut through with a thin, handheld blade; therefore other methods must be utilized. A hand-saw or small electrical saw can be utilized to separate small colonies from their parents.
BREAKING: There are many methods of breaking hard branchy corals, though only one that I personally recommend. Using a small hammer and a small chisel, one can tap-off small branches resulting in less damage and a cleaner break as compared to other methods of breaking.
SNIPPING: Snipping is really a break/cut method performed by utilizing sharp but strong shears or tin snips. It is best utilized on thinly-branched, hard corals and gorgonians. It can also be used when propagating polyps that have developed on small poly stony corals.
DRILLING/ETCHING: This method is by far the most advanced method described here and is utilized for various hard stony corals. Basically, a drill is used to etch a thin, vertical line around the base of the coral skeleton (no live part of the coral is cut). Then a small hole is drilled through the skeleton midway along the etch mark. A small wedge can then be forced slowly into this whole until the skeleton base cracks. This must be performed carefully as to not damage the coral tissue. Some limited damage may result but this can be controlled by performing this action carefully. The coral is then returned to the system but one of the pieces of its base are placed slightly lower than the other, creating tension that slowly stretches the tissue between the two bases. Over the next two weeks or longer, the pieces are moved further and further away from one another as the tissue slowly stretches resulting in a thinner connection and an eventual separation. This is the only safe method for separating a single colony of small polyp stony coral that I would suggest and let me emphasize patients in performing this technique.
After our fragmented corals have been separated from the mother colonies, they must be attached. As mentioned previously, there are numerous methods for attaching coral fragments. Some of them are:
GLUING: Utilizing various quick-setting glues (super-glue for example), cements and underwater epoxies, we can attach coral fragments to various bases including cement plugs (made with Portland type I/II cement), coral rubble, various substrates, rock-work and even the aquarium glass itself! Unfortunately, not all corals can be attached nor will accept this method; however it works great for various hard branching species.
MESH MATERIAL: Soft mesh material similar to aquarium netting can be used to temporarily wrap fragments to various objects giving them the time to attach on their own. This method is great for xenia and mushrooms. Once attached, the netting can be removed or cut away. Keep in mind that some netting may become attached to coral, and this is ok. Just cut away exposed netting. The reaming material covered by the coral will cause no harm.
STITCHING: Using dental-floss or other medical-grade strings, some species can be stitched to new bases with the use of a needle.
IMPALING: Plastic tooth-pics can be used in a similar manner to stitching to hold some species to substrate or other bases (Note: Do not use wooden tooth-pics as these can irritate coral tissue)
COLLARING: This method is sometimes utilized in combination with other methods. Basically, a protective border is placed around the fragment to hold it in place and protect it from other organisms. Common collars are derived from PVC rings or plastic cups filled with gravel or coral rubble.
Newly propagated fragments must be cared for carefully to ensure that they have the best opportunity for survival and growth. Ideally, they should be placed in lighting slightly less intense than mother colony and a medium current as compared to original placement. This will help ensure a better recovery rate.
Keep an eye on newly propagated corals as well as mother colonies for the production of excess mucous. This can easily be gently blown away with a small powerhead or a wave of a hand. Doing this will lessen the likelihood that infection may set in.
KEYS TO CORAL PROPAGATION
Select only mature, healthy specimens to be propagated
Propagate only one species of coral at a time to lessen the chance of cross-contamination through mucus production of harvested corals
Thoroughly clean all equipment before moving to a new species if more than one species is to be propagated.
If possible, maintain newly propagated corals in same system as parent colony to lessen stress and improving chances of recovery.
Research all aspects of propagating for the particular species you intend to propagate. Have a plan!
Keep a log of all coral propagation. Keep track of date fragment was propagated, size, etc. This is very helpful for reference later down the road.
Share your research and results with others!!!!
At a later date, I will include in-depth articles on propagating various species along with pictures and methods for propagation. If you have any photographs of actual propagating, I would love to include them!