Fragging (coral propagation)
The technique of cutting fragments from a mother coral to create new colonies. It allows you to multiply corals without taking them from nature.
Detailed explanation
Fragging (from fragment) is the vegetative propagation of corals. A piece is cut from a mother colony and glued onto a support (plug or disc) where it will grow as an independent colony.
For soft corals it's very simple. A clean cut with clean scissors produces a fragment that reattaches itself to a rock within days. Zoanthus, Mushroom, Sinularia: they all propagate this way.
For LPS fragging requires more attention. Euphyllia are propagated by separating the heads with a Dremel or coral band saw. Acanthastrea can be cut with a Dremel along the septa of the mouth. The fabric should be cut cleanly to minimise stress.
For SPS fragging is the most refined technique. Cut sprigs of Acropora with wire cutters or Dremel and glue them onto ceramic or aragonite plugs with cyanoacrylate glue (super glue gel). The gel glue is safe for corals and hardens even underwater.
The fragment should be placed in an area with moderate light and gentle flow for the first few weeks. As soon as the plug begins to encrust (i.e. the tissue expands on the support) it can be moved to its final position.
Fragging is the basis of the exchange and trade of corals between aquarists. Frag swaps are events where enthusiasts exchange fragments of rare corals.
Captive propagation reduces pressure on natural coral reefs. Many corals on the market today are captive propagated (CP), that is, fragments of corals already in the aquarium and never taken from nature.