GTK Aquatic: June 2012

Xeniidae Day

Genus Xenia & Anthelia.

Piece of live rock with multiple Xenia sp. colonies.
Photo credit: ReefCentral archive.

The Xeniidae group of corals, mostsly represented in the hobby by the two Genus' Xenia and Anthelia are EXCELLENT beginner corals, due to their nutrient uptake, adaptability, and low sensitivity to imperfect water quality. Species from the Genus Xenia are known to melt with no prior indicatioins or water quality issues. Species from the Genus Anthelia are some of the easiest corals to keep in aquariums.

Metallic blue Anthelia coral.
Photo credit: Airwolf75, via ReefCentral.

Genus Xenia corals are very sensitive to rising temperatures. Good flow on these corals increases health.

"Although they may tolerate a slow climb from comfortable tropical temperatures in the 70's F to the low 80's F, a sudden spike of more than 3 or 4 degrees F, particularly into the mid 80's or higher, can often prove to be fatal. There are several serious aspects to this. The first and most obvious concern is the decrease in dissolved oxygen at higher temps. Beyond stress to the system and other animals at large, corals suffer by the thickening of the anoxic microlayer that surrounds their body, by virtue of the nature of fluid dynamics (a relationship that is underestimated too commonly in reef aquaria with poor water flow). A coral can "suffocate" from such increases in the anoxic microlayer of water that surrounds them. The most common example of this is illustrated by the poor rates of survival for this family in shipping. In shipping bags, with no water movement aside from the rough handling of boxes in transit, the dynamic of decreasing oxygen levels and an increasing microlayer around the coral is amplified. The stress causes mucus to build and the mucus affords the proliferation of bacteria. The bacteria at first may not necessarily be pathogenic, but rather become so as they proliferate and mucus continues to increase." Anthony Calfo, 2008

A pulsating Xenia coral.
Photo credit: Joseph Weatherson

Life Support:

Genus: Xenia
Difficulty: Easy

Temperature: 72-80dF

Salinity: 1.023-1.026

Flow: Moderate

Lighting: Low-High*

Water Quality: Low-Moderate

pH: 8.1-8.4

Alkalinity: 8-12dKH

Aggression: Low

Genus: Anthelia
Difficulty: Easy

Temperature: 72-80dF

Salinity: 1.023-1.026

Flow: Low-Moderate

Lighting: Low-Moderate

Water Quality: Low-Moderate

pH: 8.1-8.4

Alkalinity: 8-12dKH

Aggression: Low

*A wide range of lighting conditions have been described as successful. Genus Xenia is a highly photosynthetic coral, containing some of the highest recorded concentrations of zooxanthellae of any coral species. (Calfo, 2008)

Xenia living and multiplying in a small, low tech tank. Xenia will stretch in low light conditions such as in this photo
to gain more access to the light for the zooxanthellae.
Photo credit: Joe Pusdesris, via ReefCentral.

Distribution:
Xenia corals can be found from the east coast of Africa, through the Red Sea and across to the South Pacific. Anthelia are mostly found in deeper water (20m and below) in the Indo-Pacific region.

FAQ:

Do they have sweepers? No. Neither Xenia or Anthelia use sweepers.

Do Xenia feed off of nutrients in the water as well? Yes, Xenia have a small feeding structure to conduct nutrient uptake.

Do both Xenia and Anthelia pulsate? No, only Xenia (of the two Genus') will pulsate.

Why do Xenia pulsate? It is unkown at this time, although there are many theories regarding light and nutrient uptake.

Why did my Anthelia just explode!!!? Although there is no proven theory for this, most believe that this is likely a form of reproduction or a reaction to stress. Often, the fragments will recolonize where they land.

Do fish eat these corals? Many fish, especially Angels and even Tangs, enjoy nibbling on Xenia corals.

Propogation:

Photos:

Pom-Pom Xenia.
Photo credit: Greg Rothschild, via Reefkeeping.com

Giant Anthelia.
Photo credit: James Fatherree, via Reefkeeping.com

Xenia coral.
Photo credit: ReefCentral archive.

References

Calfo, Anthony. (2008). To Pulse or Not to Pulse? Identification and Behavior of Xeniid Corals in the Aquarium Hobby. Rerieved from:

http://reefkeeping.com/issues/2004-02/ac/feature/index.php

Photo References

Greg Rothschild. Retrieved from:

http://reefkeeping.com/issues/2004-02/ac/feature/index.php

James Fatherree. Retrieved from:

http://reefkeeping.com/issues/2004-02/ac/feature/index.php

Joe Pusdesris. Retrieved from:
http://www.reefcentral.com/forums/showthread.php?t=1680646

Joseph Weatherson. Retrieved from:
http://reefkeeping.com/issues/2004-02/ac/feature/images/Xenia.gif

Airwolf75. Retrieved from:
http://www.reefcentral.com/forums/showthread.php?t=1739541

Toadstool Day

Sacrophyton sp.

A Clownfish hosts in a Toadstool coral in a ReefCentral members aquarium.
Photo Credit: shifty51008, via ReefCentral.com

Life Support:

Difficulty: Easy

Temperature: 72-82dF

Salinity: 1.023-1.026

Flow: Moderate

Lighting: Low-Moderate

Water Quality: Moderate

pH: 8.1-8.4

Alkalinity: 8-12dKH

Aggression: Low

Max Size: 3.5ft diameter

FAQ:

Do they have sweepers? Yes.

Why is mine "shrivelled"? It is a normal process, which happens once or twice a month to help eliminate algae.

Is it safe to propogate in tank? Debatable topic, consensus is that if you have carbon running, it may be safe. Most hobbyist will remove from tank and propogate in seperate container due to slime it extrudes when cut.