Sun Coral

Sun corals, also known as Tubastraea coccinea, belong to a genus of corals known as large-polyp stony corals. These stony corals produce a hard skeleton; they do not create reefs. These corals are different in that they catch all their food using long tentacles, extending them at night to feed, not by using sunlight. This specialized carnivorous feeding system makes Sun Corals heterotrophic, feeding mainly on zooplankton.

This species is known by many names, including Orange Sun Coral, Sun Polyp Coral, Sunflower Coral, and Orange Cup Coral. Read on to learn more about this colorful non-photosynthetic species

Appearance

Sun Corals have an orange body with orange and yellow transparent tentacles. They live in colonies with multiple polyps or individual bodies. They get their name from the bright yellow coloration and sun-like appearance of each polyp. The mass of growing corals maintains connection by a shared tissue base. This is a large-polyp stony coral, creating its own calcium carbonate skeleton. This skeleton is covered in corallites, which are skeletal cups formed by the individual stony coral. The polyp sits in and can retract into the corallite.

Colonies of Sun Coral grow to about five to six inches in diameter. These colonies grow by spreading out at a rate of one inch per year, forming larger communities. Individual polyps are about one inch in diameter and range from one to three inches in height.

Their polyps, the individual coral animals, extend from a skeletal cup or tube. These polyps possess numerous tentacles, often tipped with white or contrasting colors, creating a delicate, flower-like appearance. When feeding, their tentacles extend outwards, resembling a miniature underwater garden swaying in the currents. At night, this spectacle intensifies as the polyps expand to capture prey.

The species of tubastraea are the most aggressive feeders and can be fed a wide array of meaty foods.

Habitat

The Sun Coral was first documented on the reefs of Curaçao and Puerto Rico in 1943. Since then, it has become known as an invasive species in many areas. It is commonly found in Caribbean reefs and is native to the Indo-Pacific including Fiji, Tonga, Solomon Islands, and the Great Barrier Reef. It has been introduced to every continent except Antarctica due to its unique ability to live and thrive without sunlight in many different habitats.

Sun Corals are highly adaptive and can be found in waters that are sunny and shallow, displacing other native reef species, to depths of over 200 feet and colonizing many different surfaces in the deeper water, such as metal, artificial structures, caves, overhangs, and shipwrecks.

This coral was first introduced to the Gulf of Mexico in 1945. By the 1980s, the species had spread throughout the Caribbean and south Atlantic oceans. Because of its ability to survive on foreign surfaces, its invasive behavior has been highly correlated with the oil and gas industry. The stony coral attaches itself to oil platforms, which are then transported between the Indo-Pacific and the Gulf of Mexico.

Diet

Since Sun Corals do not photosynthesize for food, they have to catch all their food using long tentacles. They are known to extend their tentacles at night to consume zooplankton.

Zooplankton consists of small animals immature stages of larger animals, and other particles that are unable to swim against currents. Because of this unique filter-feeding system, these corals need to live in areas with strong currents and water flow.

Reproduction

Upon reaching sexual maturity at about 1.5 years old, the Sun Coral has three ways it can reproduce. Firstly, the asexual reproduction in which each colony is capable of creating a polyp bud or ball. These buds will eventually break away to form their own separate colony.

Secondly, this species is capable of hermaphroditic reproduction by delivering larvae of both sexes into the water column. These will settle elsewhere, as polyps, forming their colonies. Thirdly, this coral can release a thin tissue with no polyps, called a runner. These runners grow up to 4 inches per year, sometimes growing for years until they reach an open area to start growing polyps and forming a colony.

Threats

In 2006, the Sun Coral Project of Brazil began to assess the threats to local diversity among the reefs and the ocean floor. The project aims to monitor the spread of the coral and its impact on native species, provide education about invasive species and their threats, and provide the management of coral populations by removing colonies.

Their special small feedings require the corals to be fed often and by hand. They appear to do best when mimicking their natural environment, such as reef ledges and next to power heads for water flow when placing them in the tank. Keepers need to hand feed or feed them using a turkey baster their corals with items such as brine shrimp, very small fish, copepods, mysis shrimp, and small pieces of clam and scallops.

5 More Fantastic Facts about Sun Coral

1. The Sun Coral is a popular species for aquarium keepers due to their stunning displays of color and their lack of need for special lighting.
2. Their popularity is rooted both in their beautiful appearance as well as the challenge to keep them alive and thriving.
3. They open typically at night with big yellow flowers.
4. Sun corals are the common name often used to refer to corals within the genus Tubastraea. 
5. Sun Corals can be kept in very low lighting in a home aquarium. In fact, in areas of high light, they can quickly be damaged.

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