Trachyphyllia geoffroyi, also popularly known as the Open Brain Coral, is an attractive, large polyp stony (LPS) coral species renowned for its vibrant colors and intricate details. Often considered a jewel of the marine aquarium hobby, this coral is highly sought after for its unique visual appeal and its relative hardiness compared to other coral species. Its ability to adjust to various lighting and water conditions makes it a suitable choice for both beginner and experienced reef enthusiasts.
Trachyphyllia geoffroyi is also known by a number of common names in the aquarium hobby, including:
Trachyphyllia geoffroyi is a free-living coral, meaning it is not attached to the substrate. It has a hemispherical, solitary polyp that can grow up to 20 cm in diameter. The surface of the coral is covered with convoluted valleys and ridges, with the valleys often brightly colored.
A unique feature of T. geoffroyi is that it displays bilateral symmetry, which is uncommon among most coral species. Its skeleton is solid and dense, designed to resist damage from the shifting sands in its natural habitat.
Trade Names include:
Trachyphyllia geoffroyi is typically found in sandy or muddy environments on the lower reef slopes and lagoon bottoms. As a photosynthetic coral, it hosts zooxanthellae, a type of algae, in its tissues and depends on these for a significant portion of its nutritional needs. However, it also actively feeds on plankton and tiny organisms present in the water.
The distribution of Trachyphyllia geoffroyi is centered around the Indo-Pacific region. It can be found from the eastern coast of Africa to the western Pacific Ocean, with a presence in reefs around Australia, Indonesia, Japan, and the Philippines.
The Trachyphyllia geoffroyi is unique in several aspects. First, its vibrant colorations and intricate brain-like pattern make it a standout in any marine aquarium. Secondly, it's one of the few corals to exhibit bilateral symmetry.
Unlike most corals, T. geoffroyi is a free-living species, meaning it does not attach itself to any substrate. This makes it a fascinating subject of study, as it exhibits a lifestyle not typical among stony corals.
Trachyphyllia geoffroyi, although generally a hardy coral, does present some unique challenges for aquarists, especially in regard to placement and interactions with other aquarium inhabitants.
It should be placed on the sand bed as opposed to directly on the rockwork to mimic its natural habitat and prevent injury to its soft underside. They also need space around them as they can inflate larger than their skeleton size. Trachyphyllia geoffroyi is a free-living coral that in its natural habitat resides on soft substrates. This causes it to struggle with incorrect placement in the aquarium. It is not a coral that can attach to rocks, and if forced to live on a hard substrate, it can develop injuries on its underside, leading to tissue recession and possible infections. Always ensure that it is placed on a sandy substrate where it can freely adjust itself.
This coral appreciates moderate lighting. While it can adjust to different light levels, sudden changes should be avoided to prevent stress. While this coral does require light to photosynthesize, Trachyphyllia geoffroyi in nature is usually found in deeper or more shaded waters, so it can be sensitive to overexposure to light in the aquarium. Rapid introduction to high intensity lighting can cause photo-inhibition or even bleaching.
Moderate water flow is ideal for T. geoffroyi. Strong water flow can cause damage to its soft tissue.
While it obtains a large portion of its nutrition from the zooxanthellae within its tissues, supplemental feeding of microplankton or fine coral foods can be beneficial.
Fragging, or fragmenting, Trachyphyllia geoffroyi is generally not recommended due to its unique biology. This is because Trachyphyllia geoffroyi is a solitary coral species, meaning each polyp is an individual organism.
Unlike colonial corals that have multiple polyps on a shared skeletal structure and can be fragmented easily, solitary corals like Trachyphyllia geoffroyi consist of one polyp on a single skeleton. Attempting to fragment a solitary coral like this often results in high mortality rates, as the coral does not have the ability to regrow from a fragment in the way that colonial corals do.
In nature, Trachyphyllia geoffroyi reproduces primarily through a process known as “budding” where a second mouth forms and grows into a separate individual over time, eventually detaching from the parent coral.
Updated classification: Wellsophyllia radiata is now Trachyphyllia geoffroyi (*1)