The Torch coral, Euphyllia 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.
Introduction to torch coral care
E. glabrescens 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.
They require typical reef aquarium water parameters, including a temperature around 78 degrees, a specific gravity of about 1.025, a pH of about 8.2, and a calcium level of about 400 ppm.
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.
Common names: Torch, PomPom, or Trumpet, which is why common names are sometimes challenging in this hobby, because other corals have similar names
Scientific names: Euphyllia glabrescens, which means they are in the same genus as Hammer, Frogspawn, & Bubble corals.
Care level: Requires moderately challenging care
Light level: Does best with a moderate intensity of light
Flow level: Prefers a moderate water flow
Aggression: Aggressive–will sting neighbouring corals, with one exception: they will tolerate other Euphyllia corals torch coral LPS
Feeding the Torch coral
The torch coral is a photosynthetic coral, meaning it has a relationship with symbiotic zooxanthellae (single-cell photosynthetic organisms) that live inside its tissues that converts the light energy into sugar. In exchange for a home inside the coral, the zooxanthellae split their ‘harvest’ and feed the coral. Therefore, it is possible to keep the Torch coral without any feeding at all. However, all corals are animals, and animals are meant to eat. So while it is technically not necessary to feed them, the fact that they are biologically able to consume rather large, meaty meals, by coral standards, suggests to me that feeding of appropriately sized fare should be strongly encouraged.
Placement in the reef tank
The best placement for a torch coral is in a location that gets moderate water flow and moderate-intensity lighting. You don’t want the lights or the water flow to be too hot or too cool, you want them just right. What does that mean exactly?
Well, the fringes/corners of your tank (unless right next to a powerhead or light source) are likely the lower flow, lower light areas of your tank. The areas directly in front of the flow of your powerheads or gyre pumps are likely areas of highest flow.
Moderate flow is achieved in the locations where the polyps are fully extended and gently swaying like they are in a breeze. Not still or bending like they’re in a storm, but swaying in a breeze.
Moderate light intensity
The upper areas of the live rock (high up in the tank) and areas most centrally located under your LEDs are likely the highest areas of light intensity. Assuming you have high-quality Reef LEDs, Metal Halides, or T5s, those areas of most intense lighting are best reserved for the light-hungriest corals (certain SPS, and generally brightest colour corals…although that is a loose rule of thumb).
The best placement for your torches would generally be the middle-to-lower ends of the tank, still in reasonably bright light but not straight under the most intense section of the light.
Place them where both of those conditions exist
The best places in your aquarium, therefore, are where the lighting and water flow are both moderate. This may be anecdotal, but I have observed these corals 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.
Torch corals are compatible with just about any reef safe saltwater fish that won’t consider it food.
When keeping them with other corals, it is best to give them a wide birth. Torches are aggressive corals that protect themselves by wielding their sweeper tentacles maliciously. Sweeper tentacles are specialized tentacles that extend much larger than the typical tentacles and are equipped with stinging cells. Torches will send out these long tendrils to zap anything nearby within reach.
As mentioned earlier, Torch corals are part of the Euphyllia genus, and while they may try to sting and kill other neighbouring corals that grow a little too close for comfort, they will grow very well next to Hammer and Frogspawn corals.
A note about leather corals
As a general rule, caution should be used when mixing leather corals and LPS species, like torches. Many leather coral species produce and release toxic chemicals, called terpenes, into the water to protect themselves and to stunt the growth of other species. Note a few sections have died back on this torch coral specimen shown below. This is likely due to a combination of starvation/insufficient light, and possibly chemical warfare between other coral species in the tank
Aggression and sweeper tentacles
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.
Anticipating 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.
A coral that has sustained damage to the large fleshy polyps may get a brown jelly infection (which looks as gross as it sounds). You should move that individual to quarantine the infected branches right away and frag the healthy branches to save the colony.