[Ebook] Encyclopedia of Aquarium & Pond Fish – Directory of Marine Invertebrates – Corals

Directory of Marine Fish

Corals

Corals form the centerpiece of any reef aquarium. A coral is a colony of linked organisms called polyps. In stony corals, which form the foundation of the reef, the polyps have a hard body casing of calcium carbonate, while the polyps of soft corals are supported by a less rigid calcareous structure. Corals need plenty of space, and overcrowding will hinder their growth. Many corals contain symbiotic zooxanthellae (algae). When the algae photosynthesize, they provide food for both themselves and the coral, so good lighting in the tank is vital. If a piece of coral breaks off, it can be used to establish a new colony elsewhere in the tank.

Bubble Coral (Plerogyra sinuosa)

• ORIGINS: Extends from the Red Sea eastward through the entire Indo-Pacific region to Samoa.
• SIZE: 39 in (100 cm).
• DIET: Symbiotic, with internal algae providing food. Will also feed on plankton and brine shrimp.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 8.1–8.3) with SG 1.020–1.024.

Inhabiting fairly exposed areas of the reef, these corals have a relatively low, compact shape that helps to protect them from damage. Bubble Corals, which sometimes form massive colonies, are nocturnal creatures, only putting out their polyps in search of small prey after dark. White stripes across the individual bubblelike swellings indicate the location of the stinging cells, or nematocysts.

Orange Polyp Coral (Tubastrea aurea)

• ORIGINS: Widely distributed on reefs throughout the Indo-Pacific region.
• SIZE: 4 in (10 cm).
• DIET: Shrimp and other meat-based foods. Drop tiny pieces of food into the open coral heads.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 8.1–8.3) with SG 1.020–1.024.

A stunning appearance and simple care needs make this orange coral an ideal choice for home aquariums. After transfer to a new tank, the polyps may remain closed for a week. Because Orange Polyp Corals inhabit shady areas, their bodies lack symbiotic algae, so they feed by catching food with their tentacles. Reproduction is asexual, with new polyps budding off from the base of existing ones.

Lobed Brain Coral (Lobophyllia hemprichii)

• ORIGINS: From East Africa and the Red Sea, via the IndoPacific, to the Marshall Islands in the east.
• SIZE: 16 in (40 cm).
• DIET: Symbiotic, with internal algae producing nutrients. Will take small amounts of a proprietary food.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 8.1–8.3) with SG 1.020–1.024.

A twisting, involuted appearance characterizes Lobed Brain Corals, which can grow to a large size. Their coloration ranges from grayish-blue to green to deep red. These stony corals are found on deeper parts of the reef and are nocturnal in habit. When feeding Lobed Brain Corals, it helps to use a pipette so that the food can be placed directly in the vicinity of the coral.

Flowerpot Coral (Goniopora species)

• ORIGINS: Occurs widely throughout the Indo-Pacific, from the Red Sea and East Africa to Fiji and Samoa.
• SIZE: 8 in (20 cm).
• DIET: Plankton and symbiosis; good lighting conditions are vital to ensure that the internal algae are healthy.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 8.1–8.3) with SG 1.020–1.024.

The color of this stony coral varies, depending on the color of the zooxanthellae in its polyps. If gray blotches appear, however, this may signify the onset of a serious illness. The polyps, which are permanently extended, are long, delicate, and featherlike. This coral likes strong currents and bright lighting, but there is a risk that it may be attacked by external algae under such conditions.

NIGHT BLOOMING

Corals may reproduce either asexually, by a process known as budding, or by sexual means, which enables them to spread farther afield. The problem with sexual reproduction is that when a female coral releases an egg (as shown here), the currents around the reef make the chances of the egg’s coming into contact with sperm relatively slight. To improve the chances of fertilization, entire coral populations simultaneously release their gametes, using the lunar cycle to coordinate this mass reproduction. In fact, they are so prolific that the sea temporarily turns white with eggs and sperm, greatly increasing the likelihood of fertilization. This phenomenon is called night blooming. The young coral larvae drift away on the current to colonize new reef areas.

Pulsing Coral (Xenia species)

• ORIGINS: Ranges from the Red Sea eastward to the Indo-Pacific region, including the Philippines.
• SIZE: 3 1⁄2 in (8 cm).
• DIET: Mainly symbiotic; good lighting conditions are vital to ensure that the internal algae are healthy.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 8.3) with SG 1.020–1.024.

A delicately branched appearance typifies this treelike coral. The permanently extended polyps move continuously during the daytime, not in search of food but to create water currents that will bring oxygen to the coral. As with other corals that live by symbiosis, the Pulsing Coral needs bright lighting and good water circulation. Any nitrate in the water will harm this coral.

Cauliflower Coral (Pocillopora damicornis)

• ORIGINS: Extends from East Africa and the Red Sea throughout the Indo-Pacific region.
• SIZE: 4 in (10 cm).
• DIET: Filter-feeder, requiring very fine particles of food that it can sift from the water.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 8.1–8.3) with SG 1.020–1.024.

This attractive coral is named after its cauliflowerlike growth pattern. The Cauliflower Coral varies from pinkish-blue to pure blue. Site this coral in the upper levels of the tank; on the reef, it normally occurs close to the surface. As with all stony corals, a special supplement containing minerals, such as calcium, and trace elements, including strontium, should be added to the water.

[Ebook] Encyclopedia of Aquarium & Pond Fish – David Alderton (Photo by Max Gibbs)