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HOW TO TROUBLESHOOT PROBLEMS WITH HAMMERS, TORCHES, & FROGSPAWN
Hammer, Torch, and Frogspawn Troubleshooting Guide
Hammers, torches, and frogspawn are some of the most popular large polyp stony corals in the reef aquarium hobby. They range in difficulty, but for the most part they are suitable for beginners, and many hobbyists new to reef aquariums have kept them successfully. That said, problems do arise, and when they do, they can escalate quickly. This is a troubleshooting guide to help you diagnose and address the most common issues with these corals.
Before we jump into specific problems, it helps to set expectations. Within these two genera, Euphyllia (torches) and Fimbriaphyllia (hammers and frogspawn), there is a ton of variety. They cover such a large geographic range that you have them growing in very different conditions, and that variability carries over into the aquarium.
Specimen Selection
Given the variability of these corals, understanding what you have goes a long way toward diagnosing problems.
Torches are in a class of their own. At one time all of these corals were lumped into a single genus Euphyllia, but it's pretty clear that torch corals are fundamentally different from the others. They tend to be more delicate than hammers and frogspawn, and they are substantially more aggressive. You can keep most hammers and frogspawn in close proximity to one another, but I would not recommend keeping torch corals close to either of the other two.
Growth form matters. There are both branching and wall growth forms of hammers and frogspawn. The branching varieties are considerably more hardy than the wall varieties. In my experience, wall varieties grow much more slowly and get infections and diseases more frequently.
Collection origin matters. Indonesian varieties tend to be easier to keep and are fast growing, while Australian varieties tend to be more sensitive and much slower growing, and that includes the branching types. Depending on what you have, you may be more or less likely to run into problems.
If you purchased your coral from a retailer and don't know the collection origin, it's worth asking. Many retailers, especially those selling named varieties, can tell you whether the coral is Indonesian, Australian, or aquacultured. Aquacultured specimens (corals that have been grown in captivity for extended periods) tend to be the most resilient of all, since they've already adapted to aquarium conditions.
Calibrate your expectations accordingly. An Australian wall hammer is a very different animal from an Indonesian branching frogspawn, even though they are often sold side by side.
Aggression
If you are putting together a collection of hammers, torches, and frogspawn and some of the hammers or frogspawn start looking a little rough, aggression from the torches is a likely culprit. Torches are capable of sending out sweeper tentacles that pack a punch. Also, while hammers, torches, and frogspawn are not nearly as toxic as some corals, they engage in some degree of chemical warfare with other stony corals.
There are plenty of examples of hobbyists keeping hammers, torches, and frogspawn in close proximity without issue. But the reality is that there are many species spread out over vast, disparate geographies, and we are putting them all together in a single tank, sometimes in a tight bouquet. Don't be surprised when that doesn't always work.
We give torches especially plenty of space from the Fimbriaphyllia, and in some cases space from one another. Australian torches and Indonesian torches are every bit as different as the hammers that come from those regions. It's not worth the risk. Give them more space and consider running chemical filtration such as activated carbon in case there is chemical warfare going on that you can't see.
Dipping Flatworms
The most common pest that comes on hammers, torches, and frogspawn are flatworms. There are lots of different types of flatworms that plague just about every kind of coral, so this is nothing unique. What makes flatworms particularly annoying with these corals is that dipping them is neither straightforward nor as effective as you'd expect.
Usually, chemical dips are highly effective at killing flatworms and are well tolerated by the coral. The problem with Euphyllia and Fimbriaphyllia is that they pull their tentacles in when stressed, and when they withdraw, they pull in the flatworms that are hanging out on the tentacles, effectively shielding them from the dip treatment. These are very reactive corals, so they will retract from the simple act of moving them from the tank to the dipping container. Trying to dip a newly purchased coral fresh from a local fish store or an overnight shipment, while a good idea in principle, might not be as effective as you think.
Move the coral into your dipping container and allow it to fully extend. This may take up to 30 minutes, so be patient. Once the coral is back to normal, slowly add your pest dip. You want to be as gentle as possible. The goal is to keep the coral from retracting again.
I like to use a potassium salt based dip such as Reef Primer by Polyp Lab. It is both gentle on these corals and highly effective on flatworms. If you want to be more aggressive, you can mix in 50–100 ml per liter of 3% hydrogen peroxide. I don't recommend this unless you have a specific reason to escalate, because it is significantly harsher on the coral.
There is a reason you might want to escalate. Not all flatworms are the same. There is a particularly menacing "Euphyllia-eating" flatworm that is larger than the generic types and poses a serious threat. These flatworms will kill your torch corals, and they are notoriously difficult to eliminate. When you dip, they crawl into the mouths of the coral polyps to avoid the chemical treatment.
They are much more common on wild-collected torches than on aquacultured specimens, for the simple reason that long-term aquaculture is not possible if these flatworms are present. If you have them, keep dipping and inspecting the corals and surrounding areas for eggs. This is a situation where long-term quarantine pays off enormously. After 60 days in quarantine, either the dipping worked or the flatworms killed the coral. Either way, you will not be introducing this aggressive pest into your display system.
On the other end of the spectrum, there are generic photosynthetic flatworms that hang out on the mucus coats of many different stony corals and mushrooms. They are extremely common and are more of an eyesore than a genuine threat. The stress of removing the coral and dipping it is arguably more dangerous to the coral than the flatworms themselves. That said, most people want clean corals, so dip away, but understand the relative risk.
Brown Jelly Disease
Perhaps the scariest problem that can affect hammers, torches, and frogspawn is brown jelly disease. It is a fast-acting disintegration of the coral's flesh into what looks like brown mush. Once a coral develops brown jelly, the affected portions will likely be completely dead within 24 hours or less, leaving behind a stark white skeleton.
Brown jelly is not a single disease. It is a cascade of problems culminating in rapid tissue degradation. The prevailing understanding is that it involves a combination of bacteria and Philaster ciliates that, for reasons not fully understood, shift from being normal members of a coral's microbial community to becoming pathogenic. Under a microscope, what looks like the remnants of your coral is really a dense soup of ciliates and bacterial sludge.
These organisms are present in every aquarium. Why they go from benign to lethal remains an open question. There could be a series of microscopic interactions, each one knocking over the next domino, until conditions tip into a full-blown outbreak.
The affected coral is essentially already dead. The real concern is that brown jelly can spread to neighboring corals, especially if they are densely packed. When we see a brown jelly infection at the farm, we grab a siphon and remove as much of the material as possible without disturbing the rock or skeleton. The goal is to extract the infected material while minimizing agitation that could spread it through the water column. Once the bulk of the material is removed, we take out the dead coral. Again, carefully. I put it in a container underwater and slowly lift it out to minimize disturbance.
If brown jelly is the result of a chain of factors building up over time, then disrupting a few of those factors early can prevent a total collapse. It might sound paranoid to jump on a coral that is simply not opening as usual when nothing is visibly wrong yet, but that is exactly what I recommend. If I see a coral behaving slightly off during a routine walkthrough, it goes on the calendar for a dip, and the entire system may get a fresh canister of activated carbon as a precaution. It is much better to be proactive on the front end than to deal with brown jelly on the back end.
Polyp Bailout
Polyp bailout is a dramatic stress response in which a stony coral kills off its own connective tissue through apoptosis (programmed cell death) and individual polyps detach from the skeleton. Think of it as a fighter pilot hitting the eject seat and hoping for the best. Unlike necrosis, which is traumatic and uncontrolled, apoptosis is a highly regulated process. The coral is making a calculated response to a perceived existential threat.
This is uncommon, but it happens enough to be worth covering. When it does occur, it usually affects just one head on one coral, which makes pinpointing a single cause difficult.
If you see a polyp detach, you can attempt to save it. Try dipping it in a potassium-based coral dip or iodine solution to address any bacterial component, then place it in a low-flow area and allow it to settle. Be aware that the survival rate for bailed-out polyps is low.
Hammers, torches, and frogspawn are rewarding corals, but they come with a unique set of challenges. The most important takeaways: know what you're buying and set your expectations accordingly, give torches space, dip patiently and correctly, act fast and decisively at the first sign of brown jelly, and keep your water parameters stable to avoid triggering extreme stress responses like polyp bailout. When in doubt, err on the side of caution. A little paranoia goes a long way with these corals.
