News / Species Spotlight / Euphyllia Corals (05/15/14)

Euphyllia Corals

by Charles J. Hanley III


Taxonomy:
Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Scleractinia
Family: Caryophylliidae
Genus: Euphyllia



Description:
Euphyllia corals are large-polyped scleractinians (LPS) that have been a staple reef tank inhabitant for some time3, 7, 8. These stunning, branching hard corals have substantial tentacular crowns that create an impressive mass of gelatinous, fluorescent polyps. Generally hardy and easy to propagate, it is not surprising that Euphylliads are such a popular choice for beginners and experts alike6, 7, 8. Though they are often lumped into one of three groupsHammers, Torches, and Frogspawnsthere are actually over 8 separate species and multiple colorforms available in the aquarium trade.

With the polyps extended, a healthy Euphylliad will create the impression of being a single, large organism. In fact, most are colonies of small, separate heads that dramatically expand during the day. Each tentacle has one to several small tips, which are often a contrasting color to the rest of the structure. Coloration ranges from transluscent to brown, pink, green, yellow, or buff7. Skeletal formations vary from species to species, as do the shapes of the tentacular tips. Hammer corals (E. ancora, E. parancora, E. paradivisa) have hammer, sickle, or anchor shaped tips on their tentacles. Frogspawn or Octopus corals (E. divisa), on the other hand, have tentacles with multiple, hemi-spherical tips. Finally, Torch corals (E. glabrescens) have long, slender tentacles, each having a single rounded tip6, 7, 8.

The tips of the tentacles fluoresce with heavy brilliance under metal halide, actinic, or LED lighting regimes5, 6. Upon close inspection, small specks of fluorescence can also be found along the tentacular shafts of E. glabrescens6. The visual appeal of the wobbly, wavy fluorescence really makes Euphyllia corals really pop. Because they are so hard to ignore they often become a centerpiece coral, even when they are not intended to be!

Natural Habitat and Ecology:
Euphylliads are hermatypic corals (i.e. they contain symbiotic zooxanthellae algae) from the worlds Indo-Pacific region1, 4, 7. Usually found in shallower reef environments such as lagoons, they do well with medium metal halide or VHO lighting1, 4, 7, 8. They will also readily adapt to the more moderate light of T5 or power-compact fluorescents, if located sufficiently high in the water column and given supplemental actinics4, 6, 7. Though zooxanthellae provide most of corals nutrition, Euphylliads will also benefit from occasional feedings. Live and frozen foods are appropriate, but should be provided as small meaty particles such as mysid or brine shrimp1, 4, 7. Turning water flow off while feeding will help your Euphylliads catch food, as they use a mucous film to ensnare particles4.

Reproduction is achieved sexually and asexually in the wild8. It is unusual, though not unheard of, to witness spawning amongst captive specimens6, 8. More commonly, healthy animals exhibit asexual reproduction via fission and budding. Though the oral disc is often hidden, during a fission event a translucent bubble-like structure may develop on it6. Often two transverse mouths will become visible at this time. After several days, the tentacular crown will begin to split while the skeleton will develop a growing cleft. In this manner, a single polyp can multiply quickly to form a colony. Budding also occurs beneath the tentacular crown, near the base of the tissue4, 6.

Aquarium Care:
Like other scleractinians, they are important reef-builders. As such, they require supplementation of micronutrients like calcium, magnesium, strontium, and iodine2, 4. Generally, a quality two-part or all-in-one additive will suffice. Euphylliads also prefer superior water quality conditions with nutrient-free water. However, their lagoon origins make them hardy to some fluctuations in nutrient load, salinity, and temperature1, 4. Water flow should be moderate and diffuse, but can be varied from sluggish to fair with rotating powerheads and/or wavemakers7.

More importantly, Euphylliads should not be subjected to direct or heavy water flow6. Their sharps skeletons can cause potentially lethal damage to their tissues. They must be handled with care when moving, being held upside down by the skeleton. It is not advisable to remove them from the water, as their heavy tissues can be ripped free from the hard base6. It is also a good idea to secure the animal to your aquascape with aquarium safe epoxy or putty, so that it cannot become dislodged and damaged by a fall. Damaged tissue may become susceptible a brown jelly bacterial infection1, 6, 7. Rapid Tissue Necrosis (RTN) can also occur in this genus1. Euphylliads can be remarkably regenerative and most problems can be addressed with a one minute dip in freshwater of equal temperature and pH1. In the event of a severe problem the safest course of action may be to remove infected heads before the affliction spreads to rest of the colony6. Also, degenerating tissue in the aquarium system may lead to a troublesome nutrient spike.

The most important consideration when purchasing a Euphyllia coral is its placement in the aquarium. Even more critical than light availability is the distance between the Euphyllia and your other corals. Euphylliads possess long, stinging sweeper tentacles. On larger specimens the tentacles can extend over 12 inches from the base1, 3, 6. Nematocysts with potent toxins will damage or kill other corals, sometimes from a single sting1, 4, 5, 6, 8. Interestingly, differing species of Euphylliads typically wont sting each other, so they may be clustered1, 6. In smaller aquariums it is necessary to prune the coral, which is easily achieved with bone cutters. So long as you don't cut through any exterior tissue, the skeleton can be trimmed at the clefts4, 6. Keeping fewer, smaller heads and orienting water flow away from other corals will help to ensure the safety of your other reef inhabitants.

Quick Notes:
  • Keep Euphylliads submerged when moving:
    • the tissue is heavy and easily torn by the sharp skeletons.
  • Provide space for sweepers:
    • those tentacles can do severe damage to other corals.
  • Prune often:
    • healthy animals will reproduce vigorously.
  • Small, meaty foods:
    • Euphylliads like meaty foods, but catch food with mucous, not tentacles.
  • Manage micronutrients:
    • additives should include calcium, magnesium, strontium, and iodine.

References:

1 Anonymous Animal Library Entry Class: Anthozoa, Subclass: Hexacorallia, Order: Scleractinia, Family Euphylliidae, Euphyllia May 08, 2007;
2 Brightwell, C.R.Marine Chemistry Neptune City: T.F.H Publications, 2007.
3Brightwell, C.R.The Nanoreef Handbook Neptune City: T.F.H Publications, 2006.
4 Goldstein, Robert J. Marine Reef Aquarium Handbook Hauppauge: Barrons, 1997.
5 Jennings, Greg. The New Encyclopedia of the Saltwater Aquarium. Buffalo : Firefly books Ltd., 2007.
6 Personal Observation 7 Shimek, Ronald L. Marine Invertebrates. Neptune City: T.F.H Publications, 2004.
8 Tullock, John H. Natural Reef Aquariums; Simplified Approaches to Creating Living Saltwater Microcosms Neptune City: T.F.H Publications, 2001.