The Torch coral, Euphylia glabrescens, is a large polyp stony coral that originates from the Indo-pacific reef regions. This LPS coral species (the torch coral), has long, flowing fleshy polyps that extend from a calcified (stony) base.
In a moderate water flow, these corals look a bit like a torch, which is where they get their common name.
Torch coral are reported to live in a range of water conditions, from turbid (murky) waters to clear waters with blazingly crips light, suggesting a certain level of adaptability and beginner-friendliness which is likely one reason these corals are great beginner corals.
In the home aquarium, the Torch coral does not have particularly challenging husbandry requirements to be successfully cared for in a reef aquarium.
Like most large polyp stony corals, a torch coral benefits from moderate water flow. The polyps will remain retracted and under inflated if the water current is too fast, because the large flowing polyps are prone to rip and tear in high or ultra-high current environments.
Feeding the torch coral
It is not necessary to feed a torch coral, although they are capable of eating fairly large (by coral standards) meaty foods.
The fact that they are biologically able to consume rather large, meaty meals, suggests to me that feeding should be strongly encouraged.
However, Euphylia glabrescens could be kept successfully in a reef tank without any feeding at all, as long as adequate lighting is provided, because their symbiotic zooxanthellae will sustain them.
Placement in the reef tank
Unless you have fairly weak lights (which begs the question…do you have the right lights for a reef aquarium?) you can place the torch coral towards the bottom of the reef tank in an area of moderate flow. Many aquarists rely on strategically placed powerheads to create a suitable flow in the aquarium.
This may be anecdotal, but I have observed these corals to be ‘happier’ when placed in the sand, versus being glued at a mid-level on the live rock aquascape. Take that observation with a grain of reef salt.
The torch coral has potent sweeper tentacles that it will send out to other corals from growing too close and will sting anything within reach with its nematocysts. Because of this, you should take care to ensure that your torch coral has enough room both now and in the future, once the corals in your tank have begun to fill-in the available space.
Reproduction by fragmenting and budding
Since the torch coral is a branching stony coral species, it is fairly easy to propagate via fragging. You can cut, saw or snap off a branch and it will grown into an entirely new colony all on its own. A torch coral frag should command a premium, compared with some of the most commonly available leather coral species, so it is a great coral to grow and trade with other hobbyists.
As a general rule, caution should be used when mixing leather coral and large polyp stony coral species, including the torch coral.
Large polyp stony corals protect themselves by wielding their sweeper tentacles maliciously. Many of the leather coral species, by comparison produce and release toxic chemicals, called terpenes, into the water to stunt the growth of other species.
There are a lot of reports of compatibility issues between leather and LPS corals.
Problems with keeping the torch coral
One of the biggest problems I have seen beginner hobbyists have is failing to account for the calcium demand for these corals. If there is insufficient calcium in your aquarium water, these corals will not be able to make their coral skeleton.
You should also never lift a torch coral out of the water, if you can avoid it. You could tear the polyps, and torn polyps are prone to infection followed by necrosis (a complete deterioration of the tissue).
Signs of the problem
An unhealthy torch coral will have contracted polyps that will eventually recede and turn into a brown goo, leaving behind an uncolonized coral skeleton.
Written by Albert B. Ulrich III–author of The Reef Aquarium Series of books: The New Saltwater Aquarium Guide, How to Frag Corals, 107 Tips for the Marine Reef Aquarium.