News / Species Spotlight / Revisited: Fungiid Plate Corals (05/28/15)

Revisited: Fungiid Plate Corals

by Charles J. Hanley III

Scientific Name(s): Fungia granulose, F. (Cycloseris) fungites, F. klunzingeri, F. Scutaria, F. concinna, F. corona, F. danai, F. fralinae; Heliofungia actiniformis; Cycloseris cyclolites, C. tenuis, C. vaughani; Ctenactis crass, C echinata; Diaseris distorta; Halomitra pilaeus; Herpolitha limax, H. weberi; Lithophyllon mokai; Polyphyllia novaehiberiae, P. talpina; Sandalolitha robusta; Herpetoglossa simplex; Podabacia crustacea

Common Name(s): Plate Corals, Mushroom Corals, Slipper corals, Tongues corals, Hedgehog Coral

Taxonomy:

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Scleractinia
Family: Fungiidae
Genera: Ctenactis, Cycloseris, Diaseris, Fungia, Fungiacyathis, Halomitra, Heliofungia, Herpetoglossa,, Herpolitha, Lithophyllon, Podabacia, Polyphyllia, Sandolitha

Description:

Plate corals are some of the most unusual and charming corals on the market. Not only are they quite amazing to look at, they are also easy to spotlight in an aquarium, since they prefer to live on open sand. They can even move themselves if they dont approve of where you put them!

Plate corals are Long Polyped Scleractinians (LPS) and are generally free-living. That is, they do not attach to rocks. Rather, they prefer to live in open sand and move around until they find a suitable location, using cilia or their tentacles. They are characterized by a flattened, oblong skeleton, or corallite, which has pronounced sharp septa that radiate out from the center of the disk. The corallite is covered by thin tissue containing fleshy tentacles and can sometimes also be round or elongate. Some species of plate coral have shorter tentacles which give a studded appearance, while others have long ones which are similar to that of an anemone. Plate corals come in a variety of solid colors and color combinations, ranging from fluorescent orange to hues of purple, pink, green, blue, brown, and beige.

Though there are a large number of genera and species in the Fungiidae family, only a few are available in the aquarium trade. Most typically, one finds short tentacled specimens of the hardy Fungia and Polyphyllia genera and long-tentacled animals from the Heliofungia genus.

Natural Habitat and Ecology:

Indigenous to the Indo-Pacific region, plate corals are mainly hermatypic and found in shallow waters, but below depths affected by strong waves. Resulting from their free-living life-style, Fungiids are more typically found on reef-fringes than in lagoons, as opposed to most other LPS corals. They especially prefer sandy or rubble-strewn areas where they can move freely about.

In spite of the occasional colonial animal with multiple mouths, most are solitary individuals. In fact, some species have nearly the largest polyps of any coral in the world. Fungiids reproduce sexually and asexually. However, in captivity most reproduction occurs asexually via fission. The adult specimen can create smaller buds, called acanthocauli, which are briefly attached to the substrate they sit upon. Eventually, they will free themselves and find a more suitable location to take up residence. If sexual reproduction does occur, it results in free-swimming larvae which settle temporarily as acanthocauli. After that, they undergo the same maturation process as individuals produced through cloning. It should be noted that aquarists have also forced asexual budding by inducing stress in the coral, usually through temporarily reducing light levels. This process takes advantage of the corals inclination to reproduce actively while under duress. However, such techniques should only be attempted by experienced aquarists since there is a chance of killing the animal instead of getting it to bud. Fragmentation may be a safer and more effective method of achieving cloning.

Some Fungiids, especially those within the Fungia genus, are relatively easily fragmented. The process does require a rotary tool with a diamond cut-off wheel, and is achieved by scoring the underside of the corallite. The skeleton and tissue should then be cleanly sheared with a sharp pair of bone cutters or coral clippers. It is advisable to place newly cut frags onto rubble or egg-crate to facilitate good water flow around the incisions. This flow will help cleanse bacteria and other pathogens from the wounds while they are healing. Plate corals are well-known for having excellent regenerative properties and can recover very quickly from fragging if it is done carefully.

Though they are hardy, all efforts should be taken to keep aquarium specimens alive. The trade in plate corals is regulated because they are found in Appendix II of the Convention on International Trade in Endangered Species (CITES). The listing may exist since dead Fungiids are popular as jewelry, but it is incumbent upon the aquarist as well to ensure that the needs of this coral are understood and well-met. In this way, we can help to ensure that plate corals are not over-harvested.

Aquarium Care:

Plate corals are generally considered to be easy specimens to care for and maintain. Like other LPS corals, they need sufficient alkalinity and calcium hardness to sustain skeletal growth. They will benefit from the use of a good quality micronutrient supplement, as well as the consistent addition of a buffer. Regular water changes will also ensure long-term health in Fungids, as they do not like fluctuations in water quality.

Fungiids will do best with medium to bright lighting. I have witnessed very healthy animals kept under T5s as well as compact fluorescents. More importantly, they should be kept on a sandy substrate with plenty of room for them to relocate. They will eventually move to a spot with the desired combination of flow and lighting.

Most plate corals are hermatypic, and gain some nutrition from symbiotic photosynthetic algae. They also eat. From the water column and nearby substrate, they will collect detritus and bacteria and move it along the oral disc to the mouth. They can also be fed meaty aquarium food like mysid shrimp or frozen alternatives. Feeding is especially critical for individuals recovering from fragging or injury.

Given the proper conditions, plate corals can do very well in an aquarium. They are generally hardy, especially the short tentacled varieties. They can grow rapidly and sometimes exceed 20 inches. Also, care should be taken to provide adequate distance from other corals as plate corals can pack a nasty sting for their neighbors. They also secrete a toxic mucous which functions in an allelopathic capacity. This toxin can be removed conventionally through good water movement and efficient protein skimming, especially in smaller systems. As such, it is not recommended to keep plate corals in a nanoreef unless it is a species tank.

References:

Anonymous. Arkive Images of Life on Earth Online. Mushroom corals (Fungia spp.). .
Anonymous. Reef Corner Online. Plate Coral. .
Fenner, Bob. Wet Web Media Online. Plate Corals, Family Fungiidae.
Goldstein, Robert J. .Marine Reef Aquarium Handbook Hauppauge: Barrons, 1997.
Hiller, Greg. Reefkeeping Magazine Online. Propagating Fungia sp. (Plate coral). .
Jennings, Greg .The New Encyclopedia of the Saltwater Aquarium. Buffalo : Firefly books Ltd., 2007.
Personal Observation
Shimek, Ronald L. Marine Invertebrates. Neptune City: T.F.H Publications, 2004.
Tullock, John H. .Natural Reef Aquariums; Simplified Approaches to Creating Living Saltwater Microcosms Neptune City: T.F.H Publications, 2001.