Propagating Euphyllia sp. (Frogspawn)


As an aquarist having nano tanks only, I have to be selective about what corals are stocked in my tanks as the wrong selection can easily outgrow the space available. In the case of the branching Euphyllia in my tank this results in crowding and stunted growth of the shaded branches. Although it's not visible in this picture below, two branches located at the back of the right colony have grown up against the glass and are not extending their polyps as much as the rest of the colony. If the branches are allowed to remain in a compromised situation, there's a real risk of infection that can spread to the entire colony. Even in large tanks, overgrowth of certain corals sometimes needs to be limited. Using the proper technique, one can fragment (frag) their Euphyllia, end up with a healthier specimen and have corals to trade or sell to other reef enthusiasts.

The original colony.

Get Your Tools Together

The first thing you need to do is prepare the tools. I use the lid of a plastic tub as a work surface. It's waterproof, contains any spills and is easily cleaned. When I first fragmented a branching Euphyllia, I would just cut them off with a wire cutter. Although this sometimes works, there's the very real possibility of cracking the skeleton lengthwise. While the coral can usually survive this trauma I decided it wasn't worth the risk of losing the coral. My next tool was the "Dremel" type rotary cutter with the blade as shown in the picture. Although this works, access is needed to cut sideways, and this was difficult in tight quarters. In my case the wheel usually broke before the cut was finished. I've since gone to using a Dremel Multipurpose Bit #561. Before using it on live coral I suggest practicing with dead coral skeletons or even small pieces of wood to get a feel for how it cuts. When using any power tool always wear protective eyewear.

Top row (left to right): epoxy putty, protective gloves, Dremel rotary bit and Dremel tool and the #561 bit.
Bottom row: hemostats and protective glasses - all laid out on the plastic container lid used as a working surface.

My favorite tool for cutting Euphyllia, a Dremel Multipurpose Bit #561.

Another useful tool is a hemostat. While the hemostat isn't absolutely necessary, I find it to be very useful, especially if the fragment has a small skeletal base that's difficult to handle while mounting. The use of gloves when working with epoxy was covered in last month's fragmenting article by Greg Hiller, and I'll refer you back to that article for further information.

Don't be afraid to start.

Hack up the Coral

Before removing any large-polyped coral from your tank it's a good idea for its polyps to be retracted, otherwise the weight of the inflated polyps can damage the coral by stretching its tissue. Working with the coral either before or after lights out would be ideal because the polyps are usually already retracted. Otherwise, the coral can be picked up and gently swished around in the tank water until the irritation causes the coral to close. The coral is then transferred to a container of tank water until you're ready to begin fragmenting. I usually do a water change prior to fragmenting so the coral is kept in the aged tank water to minimize stress.

The actual fragmenting process is quite simple - turn on the Dremel and cut off the branches you want to remove. Try to cut in such a way to maximize the available skeleton on the fragment. In the picture below you'll notice the tool is held so that splatter flies down onto the plastic and not up into the aquarist's face. I'll also caution that care should be taken in holding the coral; unlike a piece of lumber, it's difficult to clamp down a coral, so make sure you have a secure grip that will not damage the coral's skeleton.

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Use steady, even pressure - don't force the tool.
Reposition the coral, if necessary, to get a clean cut
When the frag is almost completely cut I use the hemostat to snap it off. This prevents possible damage when it comes off and hits the work surface.

Although most any rock will work for mounting fragments, with Euphyllia I prefer to hand pick a piece of rubble. It has to be porous enough so I can easily make or enlarge a hole in the rock and large enough to support a healthy growing specimen. Typically, branching large-polyped stony coral fragments tend to be top-heavy, and piling up epoxy around its base isn't always as effective or attractive as mounting it firmly within a hole in the rock. In addition, they're usually fast growing corals with heavy skeletons; a small piece of rock may work as a good base for a couple of months, but you'll end up re-attaching it to a larger rock or find it face down in the sand one day as the coral grows and expands.

The first step is to grind out the hole(s) in the rock you've chosen. Although I use a hemostat, any tool will work. Next, the epoxy putty is kneaded until uniform in color, and a small piece is placed into the hole. You don't want to fill the hole completely because room is needed to place the skeleton. The hemostat comes in really handy for holding the coral during this step because as the fragment is inserted into the hole there's really not much to grab a hold of. Once the fragment is firmly in the hole, reinforce with epoxy around the skeleton as necessary until the fragment is secure.

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The hole is filled with epoxy.
The fragment is mounted.

Be careful handling the fragment when returning it to your tank - epoxy really needs to cure for a few hours to create a secure bond. Euphyllia typically prefer low to medium water flow, and this should also be the environment to place the fragments in when returning them to the display.

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The finished product seen here a day later; note the fragment is returning to normal and is beginning to expand its polyps.

I still remember the first time a fellow aquarist gave me a captive-propagated coral fragment. The concept of raising and propagating my own corals opened to me a whole new outlook on the hobby. No longer did I need to spend serious money purchasing wild-collected corals. Stocking my tank did not have to deplete both the ocean's resources or my own financial resources.

It is at first daunting and intimidating to take a power tool to your prized coral. With the proper technique and tools it's not really that difficult or dangerous to the health of the coral, and in some situations it can result in a healthier specimen.

Happy Fragging!

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

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"Frag" of the Month - November 2006 - Propagating Euphyllia sp. (Frogspawn) -