Open Brain Coral

Folded Brain Coral, Crater Coral, Green Open Brain Coral

Open Brain Coral, Trachyphyllia geoffroyi, also known as the Folded Brain Coral, Crater Coral, and Green Open Brain CoralTrachyphyllia geoffroyiPhoto © Animal-World: Courtesy David Brough
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   The Open Brain Coral has brightly colored polyps with fluorescent properties, it will simply glow under actinic lighting!

   The Open Brain Coral Trachyphyllia geoffroyi is attractive, and unique. These corals are most often found as a free living, solitary individual living along a reef base on muddy or sandy bottoms, or in seagrass beds. They are often found living among other free-living corals in the Fungiidae family such as the popular Disk Corals Fungia sp.. Though they can form colonies, they are most often a single polyp rather than a massive expanse. Their polyps are large fleshy mantles, and they come in a variety of bright colors including yellow, red, pink, brown, blue or green.

   T. geoffroyi are known as 'secondary' free-living corals. This is because as juveniles, like most other corals, they are attached to something solid. Trachyphyllia will attach to a stone or the shell of a bivalve of gastropod. But as they grow they get heavier and then break off, becoming free-living polyps with a cone shaped bottom that helps them anchor in soft bottom environments. Some names they are commonly know by are Open Brain Coral, Crater Coral, Dome Brain Coral, Folded Brain Coral, and Green Open Brain Coral.

   The Open Brain Coral is moderately easy to care for, they only need a lower moderate light and gentle water movement. The green variety handles a moderate lighting better. They must not be placed where sand or debris will collect on its surface, on rockwork where it can fall, or anywhere that sharp objects can lacerate its tissues. The most important care that must be exercised for a long lasting and healthy coral is daily feeding. They are voracious eaters, and if not fed well can start to recede. The Trachyphyllia genus is also very responsive to fragmenting.

   Ultimately, this coral has been known to thrive and live many years in one aquarium and yet perish in another. Coral tissue receding can lead to disease, algae growth on the skeleton, and predation. This results in more receding and eventually death. This can be helped by avoiding improper placement, too high intensity lighting, and/or not feeding as often as needed.

   The science of classifying corals is an ongoing process. On the family level, the Trachyphyliidae are extremely close to the Faviidae family, especially the Moseleya genus. Because of this, Vernon says in his book "Corals of Australia and the Indo-Pacific", that its status is somewhat arbitrary. This family is distinguished by its growth form, by having large paliform lobes (which are large vertical protrusions above the septal margin), and by fine septal teeth.

   The Open Brain Coral T. geoffroyi is currently a valid species in the this family, and in the Trachyphyllia genus. However its close relative, the Pacific Rose Coral T. radiata, has been bounced around a bit more. The Pacific Rose is very much like the Open Brain Coral, but it is always distinctly round, and usually more folded in form. Its valley walls are fused and it also has a flattened bottom, rather than a cone-shaped one. Though still in the Trachyphyliidae family, it had previously been classified in its own genus as Wellsophyllia radiata, then back to the Trachyphyllia genus. There is still ongoing discussion on where it should be classified. It can be found referred to as one or the other, but generally as Trachyphyllia radiata.

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Scientific name    Family: Mussidae
   Species: Trachyphyllia geoffroyi

Distribution / Background    Trachyphyllia Coral Information: The Trachyphyllia genus was described by Milne-Edwards and Haime in 1848. There are probably 6 nominal species, one or possibly two of which are valid species. The Trachyphyllia genus has been propagated in captivity.

  • Open Brain Coral Trachyphyllia geoffroyi - was described by Audouin in 1826.
  • Pacific Rose Coral Trachyphyllia radiata - has been bounced around a bit. It had previously been classified in its own genus as Wellsophyllia radiata, then reclassified to the Trachyphyllia genus. There is still ongoing discussion on where it should be classified. It can be found referred to as one or the other, but generally as Trachyphyllia radiata.

   Where Trachyphyllia Corals Are Found: The Trachyphyllia genus is found in the Western Central Pacific in the Philippines and around Australia on the Great Barrier Reef and then south to Passage Island on the west coast.

   Trachyphyllia Coral Habitat: The T. geoffroyi are not generally found on reefs, but around islands and inter-reef areas in muddy lagoons and reef slope bottoms with gentle water flow and moderate light. They are found with other solitary or free-living corals in the Fungiidae family including the Diaseris, Cycloseris, Heterocyathus, and Heteropsammia genera. The T. radiata are found in deeper waters under shaded overhangs, from 98 to 131 feet (30 - 40 m) in depth. They are reportedly always found attached to a hard substrate.

Status  Trachyphyllia are listed on the IUCN Red List of Endangered Species as Near Threatened (NT).

Description    What do Trachyphyllia Corals look like: The Open Brain Coral T. geoffroyi forms free-living polyps that have valleys with their own corallite walls. They can have up to 3 separate mouths, reaching up to just over 3" (8 cm) across, but the width of their valleys is just under 1/2" (10 mm) across. Their septa, or the "teeth" on the inside of the corallite wall, are large and form a ridging look under the flesh. The base of the coral is cone shaped, giving away its naturally soft substrate habitat. Their polyps are large fleshy mantles, and they come in a variety of bright colors including yellow, red, pink, brown, blue or green.

   The Pacific Rose Coral T. radiata is very much like the Open Brain T. geoffroyi, but it is always distinctly round, and usually more folded in form. Its valley walls are fused and it also has a flattened bottom, rather than a cone-shaped one. They grow in colonies once mature. Colors include varying shades of brilliant metallic greens, reds, and pinks.

      The Trachyphyllia corals feed at night, extending polyp tentacles. They can be long-lived in captivity, but their actual life span is unknown.

Difficulty of Care    Trachyphyllia Coral Care: The T. geoffroyi is moderately easy to care for, they only need a lower moderate light and gentle water movement. The green variety handles a moderate lighting better. The most important care that must be exercised for a long lasting and healthy coral is daily feeding. They are voracious eaters, and if not fed well can start to recede. The polyps tentacles come out at night to feed, and may come out during the day when food is present.

Foods / Feeding    Trachyphyllia Coral Feeding: The Trachyphyllia genus, like other large polyp stony (LPS) corals, have developed several feeding strategies. Through a symbiotic relationship with a marine algae, known as zooxanthellae, they receive some of their nutrients. They also capture planktonic organisms, food particles from the water column, and can absorb dissolved organic matter.

   In captivity, T. geoffroyi can be fed at night when the tentacles are out, but they will come out during the day as well, if it senses food in the water. Feed it daily. They will eat mysis, fortified brine shrimp, rotifers, Cyclopeeze and other similarly sized meaty foods. Larger pieces than a typical mysis is not digestible, and although the animal "accepts" it, it will regurgitate it up later in the night. So use smaller foods or your coral can waste away in a little over a year.

Aquarium Care    Typical water changes of 20% a month, 10% biweekly, or 5% weekly are needed. It has been noted that 5% weekly water changes replenish many of the needed additives and it is ultimately cheaper than purchasing additives for the water. With higher concentrations of coral with calcareous skeletons though, there may be a need put in additional additives to maintain proper levels for good growth.

   The following water supplements are suggested for Trachyphyllia species: Iodine and trace minerals can be helpful.

  • Calcium:  400 to 430 ppm. If a large poly stony (LPS) coral does not have enough calcium, it will not grow. (Seachem makes a calcium additive that states 385 as sufficient)
  • Alkalinity:  3.5 MEQ/L (8 to 11 dKh, 10 is recommended)
  • Phosphates:  0, zero.
  • Magnesium:  1200 - 1350. Magnesium makes calcium available, so if your calcium is low, check your magnesium levels before adding any more calcium.
  • Strontium:  8 - 10

Aquarium Parameters   A well-feed live rock/reef environment is what is needed for your Open Brain Coral, along with some fish for organic matter production, and dissolved organics. Have an area of substrate that is free from rocks or other sharp objects to put your Trachyphyllia. Placing it in rock work can cause the flesh to be lacerated, leading to disease and death. A mature tank is recommended.

Quick Reference Chart
Lighting: Prefers Low Lighting Levels Prefers Medium Lighting Levels Prefers High Lighting Levels
Water Flow: Prefers Low Water Flow Levels Prefers Medium Water Flow Levels Prefers High Water Flow Levels
Temperament: Peaceful Temperament Semi-Aggressive Temperament Aggressive Temperament

   Be sure to have proper water movement and lighting. Provide a low to moderate and low to moderate lighting for the best health. If it tumbles from the rock work, that usually will lead to tissue damage and eventual death. Do not place Trachyphyllia corals where debris and detritus can collect on its surface. This is a peaceful species, with no sweeper tentacles.

  • Minimum Tank Size / Length: 50 gallon (190 L) or larger
  • Marine Lighting: Low to moderate
  • Temperature: 74° - 83° F (23° - 28° C)
  • Salinity / Specific Gravity: 1.025
  • Water Movement: Low to moderate, gentle
  • Water Region: Bottom of the aquarium

Compatibility and Social Behaviors   The Trachyphyllia genus is peaceful, with no sweeper tentacles. The Trachyphyllia will at times be affected by leather corals unless the water is well filtered and carbon is used to reduce the chemicals these corals produce. Some tangs and angelfish have been known to bite on this coral.

Sex - Sexual differences    Unknown.

Breeding and Reproduction   The large polyp stony (LPS) corals are hermaphrodites, male and female within the same organism, and can reproduce both sexually and asexually. In the wild they reproduce sexually by releasing eggs and sperm at the same time, resulting in a fertilized egg which then forms into a free-swimming planula larva. Eventually the planula larvae settles onto the substrate, becoming plankters. This then forms a tiny polyp which begins to excrete calcium carbonate and develops into a coral. Planula larvae are extremely vulnerable to predation, and very few survive.

   The Trachyphyllia genus are hermaphrodites. They will reproduce by forming small polyp buds at the base of the parent colony. Upon the death of one Trachyphyllia, new daughter colonies emerged a few months later from the septa (teeth on the inside of the corallite wall) of the parent coral.

   In captivity the Trachyphyllia is actually very responsive to fragmenting. It was once thought that when fragging, a mouth must be present on the newly cut section. This has been shown not to be the case. Choose an animal that has been well fed and is very healthy. Using a water cooled saw, like a ceramic tile cutter, works great. The cut needs to be clean and prompt. From a grapefruit sized colony, you can harvest about 8 to 12 frags.

Potential Problems   TheTrachyphyllia genus are is susceptible to white band disease, brown jelly disease and bleaching, leading to tissue recession if they are stressed. This can occur when they are improperly placed in an area where sediment and detritus can accumulate on their surface. This leads to the animal sloughing these particles off, which takes a lot of the animals energy, thus weakening it to the point of disease. Algae can also start to grow on the exposed skeleton which it will never fully recover from, leading to the coral's eventual demise.

   When removing the coral from the water, gently shake the animal until the flesh is retracted since the weight of the water filled flesh will tear against the sharp skeleton when exposed to the air.

Availability    Trachyphyllia Corals for Sale: The Open Brain Coral T. geoffroyi is very easy to find at pet shops and on line. The cost for online stores is around $25.00 USD per polyp and up, depending on size and color.

References

Author: Clarice Brough CFS, Carrie McBirney
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