Step 1: Selecting an appropriate coral for propagation The vast majority of LPS corals do not respond favorably to attempts at aquaculture. While some may have a branching structure that lends itself to fragmentation, many grow in a boulder-like form that allows the coral farmer no such luxury. It is imperative that the prospective coral be researched thoroughly before attempting to propagate it. Attempting to propagate the wrong LPS will almost certainly kill it. If you have in your possession what you believe to be an appropriate LPS for aquaculture, make absolutely sure it is in perfect health and you have stable water chemistry before you go any further.
Step 2: Gather the necessary items The following items should be dedicated for aquarium use only. It is unwise to use household items used in other applications for fear of contamination.
Hammer and chisel or rotary tool with a cutting wheel attachment
Scissors to cut away loose flesh (more on this in a moment)
A Tupperware container
Gel super glue
Clean cloth towel
Step 3: Cutting the coral First take the coral to be fragmented and place it in the Tupperware container with some tank water. If the coral is branching in structure, simply breaking off a branch is trivial. If however the LPS is not a branching type, another technique must be used. There are basically two methods available, what I call the "surgical" method and the "brute force" method.
The Surgical method involves using a rotary tool to carefully cut the coral's skeleton where you intend to separate the coral. This may take some time and patience, so go slowly. Once the skeleton is cut into two, there should still be the coral's flesh attaching the two halves. At this time, wedge a piece of rock between the two halves and put the coral back into the tank. Every week, place more space between the two halves until the colony totally separates. This method may take up to two months to complete. While slow, it has been shown to work on several types of LPS.
Some LPS such as Lobophyllia and Fungia can be broken apart with a much more direct method. Basically, the brute force method boils down to shattering a coral with a hammer and chisel and cutting apart the loose flesh with scissors. Obviously this technique is not for the faint of heart. It is far more stressful on the coral, but it gives instant results, and a surprisingly high survival rate amongst the fragments produced.
Step 4: Placing the mother colony and the fragment back into the aquarium Remove the mother colony from the Tupperware container and reintroduce it into the tank in a location where it receives adequate flow. Current is essential to removing the excess mucus and aiding the regenerative process. Discard the water in the Tupperware container.
The fragments from the chisel technique can be placed on the substrate in an area where they receive adequate flow. It may take a few weeks before they fully recover and close the open wounds and form new mouths.