Likely Reef Tank Suitable
There are some very good reef aquarium species in this family, i.e., the Elegance Coral in the Genus Catalaphyllia, some Euphyllia species, and an interesting species called Octopus Coral, Pearl Coral, or Grape Coral in the genus Physogyra.
As for the Elegance Coral, it is generally considered one of the most popular, most sturdy and easiest of all photosynthetic LPS corals to maintain. It was first described by Saville-Kent in 1893 under another genus name. This multi-mouth single polyp animal is almost always extended with free flowing tentacles. Some specimens have pink tipped tentacles and others have white or purple tips. The fleshy polyp is usually various shades of intense green, which is the pigment that provides its ultraviolet protection. Even though found in a variety of shapes and colors, they all belong to a single species. Most seem to come from Indonesia, however their distribution is over a much larger area.
In nature they are found in a wide assortment of environments, e.g., mud and/or sandy substrates/lagoons, seagrass beds, deep reef slopes, muddy banks, etc., with their skeleton deeply imbedded in the sediment. Since they normally reside in turbid waters they should not be placed directly under very strong light in the aquarium. They prefer moderate water circulation and will take occasional hand feedings of meaty foodstuffs. Keep in mind they are aggressive, with their tentacles covered with thousands of stinging cells called cnidocytes. These cells have a mechanism called a nematocyst (something like a harpoon), which is used to inject poison into anything that threatens or is considered food. Therefore, they require a lot of space in the aquarium. Some aquarists may experience an allergic reaction if they are stung.
Julian Sprung advocates treating newly arrived specimens of Catalaphyllia with Doxycyline in a quarantine tank or holding tank with strong aeration for a possible pathogenic bacteria. He suggests the use a concentration of 10 mg/gallon and not illuminating, as the product is photosensitive. Maintain for three days, then remove and place in display aquarium. Julian also notes that treatment can be used on a display system, but shut down the protein skimmer because the product makes it foam excessively. Leave skimmer off for 48 hours. The water may become brown colored after 24 hours, but can be removed with activated carbon. Nitrofurazone, at 25 to 50 mg/gallon in a bare holding system is also a possible treatment. Maintain for three days before removing.
In the genus Euphyllia there are two species groups. One forming "phaceloid" colonies, containing the species E. glabrescens, E. paradivisa, E. paraancora, and E. paraglabrescens. The second group (originally described as E. fimbriata), forming "flabellomeandroid" colonies, appears to include E. divisa, E. ancora and possibly E. yaeyamaensis if that remains as a valid species. This probably does not have much importance where hobbyists are concerned because there are only three species of interest to most marine hobbyists, i.e., E. ancora commonly called Hammer or Anchor Coral; E. glabrescens called Torch Coral; and, E. divisa called Frogspawn, Wall Coral, or Zig-Zag. I've also shown what I believe to be E. paraancora.
All have stinging cells known as nematocysts on their tentacles that allow it to capture small pray as foodstuffs or defend itself from potential predators. They also contain zooxanthellae and in the presence of light are capable of photosynthesizing and internally producing some of its own foodstuffs. Occasional feeding with brine shrimp, glass worms, or other meaty foodstuffs is recommended.
Anchor and Frogspawn have what is termed "sweeper" tentacles that extend far beyond their body mass and sting anything they touch. They are basically used to clear new areas for future growth. These sweepers are a good reason not to place these corals too close to other corals in the aquarium, especially those downstream from it.
They all prefer medium light intensity, will do well under either indirect metal halide or fluorescent, gentle to medium water circulation, and will not tolerate hair algae. They are also often found in lagoons with muddy substrates and turbid water. Not an easy coral to maintain, and seems to be susceptible to bacteria/fungal infections. I've also seen E. divisa and E. ancora accepted as an anemone by some clownfishes, however this does not make for a happy coral specimen! All are susceptible to RTN, and if so, can be dipped in freshwater, same temperature and pH as the aquarium for one minute. Many times this will cure the problem. The effected coral should then be placed back in the aquarium in a place where there is better water movement than where it was originally.
They are also collected by breaking away pieces of the original colony and therefore are susceptible to infection in shipment. Both E. ancora and E. divisa can co-mingle without any tissue damage to the other.
The genus Physogyra has a Bubble Coral that is sometimes referred to as the "poor man's bubble coral." This photosynthetic species, which has small bubbles, does much better in an area that receives intense light and very good water movement and is highly aggressive! Closely related to this species is Nemenzophyllia turbida, the Fox Coral, a non-aggressive stony coral that requires just the opposite environmental conditions, i.e., moderate light and gentle currents.
The more popular Bubble Coral in the genus Plerogyra has dramatic environmental differences between it and the species in the genus Physogyra, as it needs the same conditions as Fox Coral. Common names for this species include Bubble Coral, Bladder Coral, and Grape Coral and this is one of the more popular photosynthetic LPS corals. Specimens over 3 feet across have been seen in the wild. There are at least three species of bubble corals; the one mentioned below as named by (Dana in 1846), the quite rare Plerogyra simplex (Rehberg, 1892) and Physogyra lichtensteini (Milne Edwards & Haime, 1851) also rarely seen. All are related to hammer, frogspawn, and elegance corals and found throughout the Indo-Pacific and in the Red Sea.
They also come from a wide variety of environments, e.g., muddy and sandy bottom areas and attached to vertical walls. Their calcium carbonate skeleton usually forms a fattened oval or rounded shape. The more common bubble coral develops a somewhat flattened, yet continuous and unbranched wall of fused vertical plates (septa) with top area covered by the fleshy part of the animal.
The large multi-mouthed polyp is almost always extended with dime to quarter-sized water filled bubbles (vesicles) attached along its outer edge. Bubbles are usually .5 to 1.0 inch (1 - 2.5 cm), sometimes larger. Some bubbles appear to have a fingerprint pattern on their surface. At night, they retract somewhat and the coral displays long sweeper tentacles, sometimes 3 or 4 inches (7.5 - 10 cm) in length that can sting neighbors downstream that are within reach. It should be noted the short tentacles seen associated with the bubbles during the day do not contain nematocysts as does the sweepers extended during the night.
The most common color is tan, yet some species exhibit a pale green or pink tinge. Some light tan to almost white colored specimens probably received more light than darker brown specimens. Those with colored tints require slightly better lighting than brown or tan specimens. Generally, most prefer low light and do better with indirect light. Alkalinity should be kept in the 10 - 12 dKH range and phosphate, which interferes with calcium deposits, below .015 mg/l. Since the animal's septa are quite sharp, handling during collection and shipping can easily damage the skeleton or tissue material. It's always better to select a specimen that looks healthy and shows no signs of damage or tissue recession.