Propagating Fungia sp.
or plate corals, are free-living corals that consist of one
large polyp and usually a single mouth. There are 18 recognized
species of Fungia, all from the Indo-Pacific,1
and another 10 species of Cycloseris, a very similar,
though usually physically smaller, genera of plate corals.
A few species of plate corals are easy to tell apart, but
many would be difficult for the casual aquarist (like me)
to distinguish. A careful examination of the bleached out
skeleton might be necessary for proper identification, something
I usually try to avoid with the specimens in my tanks! So,
for the purposes of this article, I'm going to assume that
the specimens I work with are all Fungia, though admittedly
I do not know for certain that they are. In any case, the
techniques I discuss probably apply equally well to the many
similar genera of plate corals.
Three forms of Fungia that the author has successfully
propagated using the methods described in this article.
My first experience with Fungia was accidental. Early
in my days as a hobbyist I'd purchased a colorful soft coral
attached to a small rock. In a few weeks the soft coral had
withered away but, being lazy, I left the rock in the tank.
After a few weeks I noticed a very small polyp starting to
grow, attached to the rock. I had no idea what it was, because
it was about the size of a sesame seed. It continued to grow
for the next six months or so to about the size of a half
dollar. At that point the now recognizable Fungia broke
free from its attachment point on the rock and became free
living. It continued to grow, and retained its standard brown
color for many years. The fascinating thing for me was that
I noticed that a tiny amount of living coral tissue remained
at the point where the free-living polyp had broken free.
Over the course of the next few weeks, this living tissue
grew over the bare skeleton that was left where the coral
had detached. The tissue re-formed into another polyp and
began to grow again, soon looking identical to the way it
had before the first polyp's detachment. This went on for
several years, and I ended up with three or so babies being
"born" from this single attachment point. Eventually
I had some serious problems with a tenacious form of algae
known as Bryopsis, which is unpalatable to most herbivores.
The attachment point was overgrown with algae, and that was
the end of my Fungia "factory." Having several
identical Fungia in hand, however, I felt it was time
to experiment with some fragmentation techniques on this coral.
To this day, I still have several of this coral's daughter
clones, which I obtained from my propagation efforts.
On the reef, plate corals usually do not have the "puffed-up"
appearance that they commonly have in reef aquaria. I've also
noticed while diving that plate corals seem to be found quite
often with their mouth side down, with no particular harm
coming to them in this orientation, other than being a bit
pale if you flip them over. Perhaps the toast falls butter
side down quite often on the reef, too! On the reef, Fungia
are often found on small rock ledges, not necessarily on sand
surfaces; and only at night do plate corals completely extend
their tentacles and swell up with water as they actively try
to capture plankton. Within a few minutes captured particles
of food can be shunted along the coral's surface to its mouth.
Their mouth can open wide to allow the coral to consume surprisingly
large prey organisms. In an aquarium they are best fed at
night by slowing water motion temporarily and dropping the
food (grated seafood, Mysis shrimp, brine shrimp, etc.)
directly onto the coral. In some tanks it is necessary to
guard the coral from aggressive shrimp, hermit crabs or hungry
fish until the coral can completely engulf the food. While
feeding plate corals may accelerate their growth rate, I have
found that in the average, well-lit reef aquarium, most can
gather a sufficient amount of energy from their internal zooxanthellae
(photosynthetic symbiotic algae) and the nutrients normally
present in the tank to grow at a reasonable pace.
As with all corals, unless you are trying to save an ailing
coral by cutting out a diseased portion of it, it's best to
consider fragmenting only very healthy specimens.
Get Your Tools Together
For propagating Fungia, the
most important tool is a diamond cutoff wheel for a high speed
rotary tool. This will allow you to cut cleanly though the
coral's skeleton and minimize tissue damage. A standard diamond
cutoff wheel is made by Dremel,2
but much larger diamond cutoff wheels can be found and can
be useful for some purposes.3
It's also handy to have a pair of cutting pliers or fragging
Tools useful for fragmenting plate corals (ignore the
I usually work from the coral's underside because damaging
tissue on that side of the coral is less likely to affect
its recovery than if the top is damaged. The coral is removed
from the water and the rotary tool is used to simply score
the underside of the coral. Some heat will be generated as
the cuts are made, and it's a good idea to frequently dip
the coral back into a bowl of room temperature tank water
to keep the coral near room temperature. While this work is
not particularly dangerous, it's probably wise to work in
a well-ventilated room to minimize inhalation of the calcium
carbonate dust (and flashbacks of bad dental experiences!)
that will be generated. Once the coral is scored with the
rotary tool, it can be cut the rest of the way with cutting
pliers. The cutting pliers alone could be used to fragment
the coral, but it's quite likely that a jagged and less controlled
cut of the coral would result. I've found that for maximum
success the cut pieces should be no smaller than a nickel.
For some particularly hardy and fast growing Fungia,
however, it might be possible under the right conditions to
cut the pieces very small. Working with Fungia scutaria,
some researchers have found that even individual pieces of
septa (the tall ridges on the surface of some Fungia's
skeleton) can be snapped off, and over time can grow into
After the pieces have been separated they should be put back
into an area of the aquarium with good circulation, with conditions
similar to those to which the original colony was exposed.
There may be some advantage in placing the cut pieces on coarse
rocks rather than sand, which will maximize the water flow
around any damaged tissue and reduce the chance of a microbial
infection taking hold. Under good conditions the coral tissue
usually grows quickly over any bare skeleton surfaces exposed
during the propagation. It may be particularly important during
this time period to have good control over filamentous algae
in the tank, as Fungia are not particularly good at
competing with any algae that takes hold on their skeleton.
Fungia colony ready to be cut up.
Marks from previously performed propagation efforts
are evident on the underside of this Fungia.
A high-speed rotary tool with a diamond cutoff wheel
is used to make straight line cuts on the underside
of the coral.
Once the coral is scored, the pieces can be fully separated
using cutting pliers or tin snips. If a larger diameter
diamond cutoff tool is available, it may be possible
to cut completely through the coral, but more damage
to the living tissue is likely to occur as the heat
from the cutting "cooks" the tissue on the
coral's upper side. Photos by the author's daughter.
Unfortunately, most Fungia are fairly slow growing
corals. It might be possible to fragment a Fungia only
once every few years. Over time the corals regain their roughly
circular form, though sometimes they may have unusual skeletal
features, and sometimes multiple mouths.
Unusual skeletal patterns of propagated Fungia.
The far right photo shows the coral's underside with
the original colony's clearly visible pattern.
Other Methods of Fungia Propagation
In some cases propagation may be accidental.
I've heard of extreme cases of aquarists having poor conditions
in their aquarium and the living coral tissue on a Fungia
separating into small areas on the skeleton. When conditions
improve, each of the separate sections re-forms into its own
separate coral (anthocauli), initially attached to the original
parent skeleton. Once healthy, there is no reason these could
not be cut apart and allowed to grow into individual colonies.
I've even heard of damage from having an aquarium heater sitting
on top of a Fungia resulting in the same type of "propagation."
These are not methods I recommend, though!
Another propagation technique that has been reported to me
involves placing a Fungia in a very low light condition
for several weeks and then suddenly exposing it to very strong
metal halide light for a few days.5
The severe shock can cause a condition similar to that mentioned
in the previous paragraph - a multitude of small anthocauli
that can be separated and grown out.
The techniques I have mentioned in this article can likely
be used for most plate and tongue corals. This includes the
genera Diaseris, Cantharellus, Ctenactis,
Herpolitha, Polyphyllia, Sandalolitha
and Halomitra. It might also work on "Chalice"
corals. I have been warned away by others, but I have also
seriously considered trying my hand at fragmenting my Heliofungia
actiniformis (long-tentacled plate coral). If I'm successful,
perhaps that will be another article.
Top-down photo of the author's Heliofungia actiniformis
(long-tentacled plate coral).
1. Veron, J.E.N. 2000. Corals of the World. Australian
Institute of Marine Science, Townsville. 3 Volumes.
4. Personal communication, Rob Toonen 2006, experiments performed
by Leah Hollingsworth under the direction of Dave Krupp at
Windward Community College, Kaneohe Hawaii.
5. Personal communication, Joe Scavo, 2006.
If you have any questions
about this article, please visit my author forum
on Reef Central.