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Family Trachyphylliidae - Open Brain Corals
Hardy, Attractive Stony Corals for the Marine Aquarium

Red Open Brain Coral
The popular red morph of open brain coral (Trachyphyllia geoffroyi ) is an aquarium favorite.

Trachyphylliidae is a small family of corals with a big history of taxonomical debate. In 1977, the family was broken out of Family Faviidae, and two genera were established in the new family. These two genera, according to Dr. Charlie Veron, author of the three volume tome Corals of the World, were Callogyra and Trachyphyllia. In 1980, the genus Callogyra became Wellsophyllia (Pichon), but by the mid-1980s, Veron expressed doubts about the legitimacy of Wellsophyllia as a genus. Today Wellsophyllia is synonymous with Trachyphyllia, and the result is that Family Trachyphylliidae is now considered a monotypic family with Trachyphyllia being the sole genus.

Rough Leafs and Ocean Roses

In common terms, corals from the Family Trachyphylliidae—the family name originates from the Greek and roughly translates as “rough leaf”— are called open brain corals, folded brain corals, crater corals, and (Pacific) rose corals. Two species are generally available to the marine aquarium hobbyist; they are T. geoffroyi and T. radiate (the latter is frequently sold as pacific rose coral).

As far as the aquarist is concerned, the primary difference between T. geoffroyi and T. radiate is availability in the trade, tank placement and skeletal shape. T. radiata is less commonly seen in the trade and occurs in growth forms that are not free-living (e.g. T. radiata may be attached to hard substrate). T. geoffroyi, on the other hand, always occurs as a secondary free-living coral, meaning that it begins life as a polyp attached to a hard substrate but later detaches and establishes itself directly on a soft substrate like sand or mud. By looking at the animal’s skeleton or collallum, the aquarist can usually distinguish between the two species . The corallum of T. geoffroyi is generally conical, which is useful for establishing itself on soft substrate, while the collallum of T. radiate is flat.

The Pacific rose open brain coral ( T. radiata ) was once known as Wellsophyllia.

General Physical Description

Open brain corals are very distinctive looking with their large polyps and fleshy mantles. They are characteristically flabellate (pronounced fla-buh-late), which means their skeletons form short valleys with separate walls. Species from the Family Trachyphylliidae can be distinguished from Flavids by way of their skeletons, and, more specifically, their paliform lobes, which are quite large. These corals can expand their mantles to up to three times the animal’s skeletal size. Color morphs of green and red are most common, although rarely blue morphs make it into the trade. While both fluoresce, T. radiate is known for its especially bright green iridescence, which may be a result of this species being a deeper water coral.


Open brain corals are collected throughout the Indo-Pacific in tropical waters, and they should therefore be kept in a tropical marine aquarium with stable water parameters. Open brain corals are generally considered hardy corals appropriate for the beginning aquarist so long as a stable environment with appropriate lighting is provided. Adding calcium, strontium, magnesium, and possibly iodine supplements is recommended.

T. geoffroyi must be kept in an aquarium with a soft substrate and should be placed directly on the soft substrate where its tissue will not be abraded by the expansion and retraction of its fleshy mantle. T radita may be carefully placed in the rockwork or on a soft substrate.

While open brain corals are photosynthetic insofar as they host symbiotic zooanthellae, both of these species will benefit from supplemental feedings. Offer small meaty pieces of marine flesh that have been soaked in a vitamin supplement such as Selcon at least once a week. Feeding is best accomplished at night when the corals short feeding tentacles extend. Because open brains do host zooanthellae, they should only be kept in aquaria with moderate to high intensity lighting, although species in this family d tend to be remarkably light tolerant.

Open brain corals do not possess long sweeper tentacles, and they therefore do not need as much room as some other common corals with large polyps. Nonetheless, they can grow up to eight inches in diameter in the aquarium (though it is rare for a fully inflated mantle to reach more than one foot across.

Open brain corals do need moderate water current to help them keep sediment from settling on their tissue. Certain species of sand sifting fishes can prove problematic in that they may deposit sand on the open brain coral, which can eventually lead to tissue death.

It is best to quarantine all corals before adding them to your system. Only use medicated dips when you see tissue necrosis or any other sign of bacterial infection.

Reproduction is not unusual in the aquarium with budding of new polyps at the base of the skeleton and then breaking off.

Published 24 June 2008. © Blue Zoo Aquatics

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