Class Anthozoa, Order Alcyonacea, Family Xeniidae, Genus Xenia
Common names: pulse coral, Xenia
Natural origin: Indo-Pacific
Sensitivity (Level 1): Though generally very easy to care for,
these corals can be somewhat unpredictable. Some colonies
show impressive tolerance and forgiveness of varying
conditions while others do not. They are also notorious for
sudden and unexplainable death and do not ship well.
Feeding: Specific feeding habits are largely unknown. They
are thought to absorb nutrients through their soft tissue
(possibly aided by the pulsing of the coral).
Lighting (Level 6 to 10): Xenia can adapt to a wide range of
lighting conditions, but seem to prefer more intense lighting.
As always, be sure to properly acclimate to knew lighting.
Water flow: Moderate to high water flow is important.
Higher water flow may increase pulsing activity.
Placement: Though not aggressive corals, like star polyps,
they are relentlessly fast growing when healthy. They can
become a nuisance in tanks with slower growing stony corals.
When injured or dying, they can release toxins. Carbon
filtration and prompt removal of injured/dying species can
help control any ill-effects of this toxic release.
General: Pulsing activity is something of a mystery (its
function and mechanism are currently unknown). Xenia in
aquariums sometimes stop pulsing (often without observable
cause) but continue to live and grow regardless. Some
aquarists have noticed a cessation of pulsing with low pH
and/or alkalinity. Polyps will close at night and when
stressed. They may take a few days or even weeks to open up
in a new environment.
Level 1 - These corals are easy to care for, good for
the novice aquarists.
Level 2 - These corals require slightly more attention
than level 1 corals, but are generally tolerant and
Level 3 - These corals require stable, established
aquariums and care by an
Level 4 - These corals should only be kept by the
most experienced aquarists.
Level 5 - These corals are not known to be able to
survive in aquariums even when under the care of
the most experienced aquarists
Note that this scale is not set in stone, but based on the numerous
experiences and reports of professional and hobby aquarists. The
sensitivity and tolerance of any given coral in your tank will
depend on species, health when collected/purchased, how long it's
been in captivity, and other factors that may or may not be
Lighting Scale (approximations):
Level 0 - no light
Level 3 - one foot below modest VHO or T5
Level 5 - two feet below extensive VHO or T5
Level 6 - one foot below extensive VHO or T5
Level 7 - two feet below 250 watt single ended MH
light (or 150-175 watt MH with HQI ballast)
Level 8 - one foot below 250 watt single ended MH
light (or 150-175 watt MH with HQI ballast)
Level 10 - one foot below 400 watt single ended MH
(or 250 watt MH with HQI ballast)
Note that this scale is quite crude and only meant to provide a
rough idea of the different levels of light intensities. How much
(and what kind of) light actually reaches the corals in your tank
also depends on the type of reflector in the light fixture, the
temperature of the bulbs/lamps, the clarity of your tank water,
It's also important to note that different individual corals, even of the same species, can have very different lighting requirements and
ideals. Often times, the same types and species of wild caught corals come from different depths and different water clarities. It's nearly
impossible to know what kind or how much light was getting to your coral when it was first taken from the wild. One advantage of
aquacultured corals is that you can know what light they were grown under. Beyond health, the color of any given zooxanthellate
(photosynthetic) coral will change and adapt in response to the lighting it is placed under. All corals are vulnerable to bleaching if not allowed
to acclimate to a change to more intense lighting. If your coral begins to bleach, move it to an area of lower lighting and feed it especially well.
Please, always take the time to acclimate new corals.
Step 1: Float the bag with the coral in the aquarium water (away from lights!) for about 20 minutes.
Step 2: Open the bag and test the salinity of the bag water.
Step 3: Add about 1/3 to 1/2 cup of tank water to the bag every 10-20 minutes until the bag water and tank water
are approximately the same salinity. You can add less water over longer periods of time to acclimate more slowly
for more sensitive animals (or when the bag water and tank water have substantially different salinity).
Acclimation can also be done in a bucket (rather than the transport bag). However, the bucket water temperature can get closer
to room temperature than tank water temperature (especially for slow acclimations). Insulating the bucket in a Styrofoam box
or cooler during acclimation should help.
To acclimate to new lighting conditions, first place the coral in a less light intense area of the tank. Every few days, move the
coral towards more direct lighting until it is where you want it to be. If it begins to bleach at any point, move it back to a less
light intense area. After the coral recovers, commence moving towards more direct light more slowly.
These care sheets are a brief presentation of the needs and characteristics of a variety of commonly kept aquarium
corals. Though there's a lot of science in reef keeping, the hobby itself has always been and continues to be an imperfect
science. Much is still unknown and there is often more than one way to do things. Please take what's written here as a starting
point, but always keep an active and curious mind.