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Welcome to the blog for reef tank owners! This week’s topic is on how to care for your new hammer coral. The Hammer Coral is one of the most popular corals for reef tanks for their unique shape and coloration. Caring for your new Hammer Coral is easy, as long as you know what to do! In this blog post, we’ll discuss how you can care for your new hammer coral so that you can enjoy its beauty! Let’s get started!
A Quick Overview On The Hammer Coral
|Scientific Name||Euphyllia ancora|
|Common Names||Hammer coral, less commonly known as the anchor coral|
|Origin||Indo-Pacific (mainly in western regions) as well as the Red Sea|
|Common Colors||Greens, purples/pinks, browns, oranges/yellows, blues|
|Lighting||Moderate (50-150 PAR)|
|Tank Placement||Bottom, Middle|
|Temperature Range||76-82 degrees F|
|pH Range||8.0 – 8.4|
|Salinity||1.025 or 35 PPT|
|Alkalinity||8 – 12 dKH|
|Calcium Level||350 – 450 PPM|
|Magnesium Level||1250 – 1350 PPM|
Origins And Habitat
The hammer coral can be found in large colonies throughout western regions of the Indo-Pacific; some occurrences have also been documented in the Red Sea, but these populations are secondary1.
These corals prefer shallower waters with moderate flow on the reef. Hammer corals have been observed in turbid waters, but will not do well if placed in areas of excessively high water flow.
Interestingly, they can be found among other species of Euphyllia, like frogspawns (Euphyllia divisa/Euphyllia paradivisa), as well as with their own even though they contain nematocysts that are capable of stinging other neighboring corals.
However, more aggressive Euphyllia, like torches (Euphyllia glabrescens) can still cause damage to the hammer coral and will not coexist in close proximity.
What Does The Hammer Coral Look Like?
Hammer corals are large polyp stony coral (LPS) which means that they form fleshy polyps on top of calcium carbonate skeleton. These corals are one of the most popular corals in the reef aquarium hobby due to their movement in the water current and variety of colors.
Hammers can come in many colors, including greens, purples/pinks, browns, oranges/yellows, and blues. They typically have darker tentacles and lighter tips, though they can sometimes appear uniform in color.
These corals are pretty easy to identify by looking at their tips, but not all hammers look the same. Here is a list of possible tip-shapes that you can find among hammer corals:
- “T” shape. Hammer corals earn their most common name from the flattened tip that resembles the construction tool of the same name.
- Anchor shape. This shape earns them their second common name and is similar to the “T” shape. However, the edges of the flattened area pull back towards the tentacles, creating an upward curve.
- Rounded shape. A hammer coral with rounded tips can easily be mistaken for a torch coral. Though difficult to tell apart, hammers with rounded edges usually have shorter and wider tentacles than most torches.
Hammer corals can also come in branching or wall varieties, both exhibiting all tip-shapes; branching hammers will have independent polyps separated by coral skeleton while a wall hammer coral will have one solid wall of coral skeleton with connected polyps.
Placement And Temperament In The Aquarium
Hammer corals are moderately aggressive and should be given plenty of space in the aquarium.
Though they’re not as aggressive as torches, a hammer coral will extend their sweeper tentacles to keep other corals away. This sting is not completely damaging and most other LPS corals and soft corals can tolerate it, but placement should be planned to avoid eventual interaction.
The only exception to this stinging is with other species of Euphyllia. Though hammer corals will try to sting other corals regardless of species, most hammers and frogspawn coral are able to peacefully live next to one another.
If you notice that one species starts to retract more or lose its color, it’s possible that the larger colony is fighting for space and resources.
How Much Light Do They Need?
The hammer coral can be placed in most areas of the aquarium. They do best in medium water flow and medium light so that they can fully extend their tentacles. Hobbyists agree that keeping them at higher PARS in excess of 150 does not provide any benefit and can actually cause the coral to bleach.
Hammer corals can tolerate being placed on the substrate, but care should be taken to avoid rubbing and irritation from rocks or stuck granules. Due to their lower light requirements, most reef led systems should be suitable for Hammers.
Are They Easy To Keep?
Yes they are. The Hammer coral is one of the best introductory LPS species for beginner hobbyists looking to move past soft corals. They don’t require intense lighting or water flow and don’t need additional feedings. However, these corals do need stable tank parameters so a mature tank is preferred.
But what parameters will allow your coral to thrive? As always, you should strive for stability rather than ideal numbers. There are some ranges where these corals will do their best though (video source).
A Hammer coral should have access to available nutrients and will actually do better in ‘dirtier’ water. They do not require any special filtration and can be kept in tanks with hang on the back filters, canister filters, and sumps. A protein skimmer can be useful for larger tanks, though your hammer coral will probably appreciate the excess nutrients.
Because hammers like dirtier water, your water should have up to 40 PPM nitrate and up to 0.1 PPM phosphate. For best color and coral skeleton growth, other parameters should be kept at:
- magnesium: 1200-1350 PPM
- calcium: 350-450 PPM
- alkalinity: 8-12 dKH
Dosing is not usually recommended unless dealing with much larger colonies and/or a mixed reef with small-polyp stony corals (SPS). Fish waste, water changes, and other detritus are usually enough to keep your hammer coral happy!
If you are working with a mixed reef, then calcium, alkalinity, and other trace elements will be the most important nutrients for maintaining a healthy reef. Dosed parameters should be tested right after dosing and right before the next dose to measure how nutrients are being used in the tank.
Hammer corals are not big eaters and will usually rely on what’s already in the water column, like small microorganisms.
Spot feeding hammer corals can actually irritate them as larger foods cannot be quickly or easily moved into the mouth and might be initially seen as a predator. Because it takes a while for the food to reach the mouth, it is also likely that fish and invertebrates will try to take the food before it can be eaten, leading to further annoyance.
Are There Any Benefits To Feeding?
Not really. These corals are experts at finding their own food naturally throughout the tank and attempting to feed them more may just create a nutrient imbalance in your tank.
If you really want to feed your hammer coral, broadcast feed brine shrimp, zooplankton, and other coral foods only once a week. Algae Barn’s Ocean Magik is a great source for Phytoplankton.
This phytoplankton package is loaded with 4 types of phyto. Excellent for corals, fish fry, and larvae
What Are Good Tankmates?
Not only can a hammer coral be kept with other Euphyllia coral, but they can also be kept with many species of reef-safe fish and invertebrates. As long as your fish or invertebrate doesn’t have teeth, hairy pincers, or an appetite for coral, then it will most likely get along with a hammer coral.
Here are some stocking ideas for a reef aquarium that has a hammer coral:
- Damsel Fish – like clownfish, azure, and springeri damsel fish
- Tangs – like yellow, powder blue, and hippo tangs
- Anthias – like lyretail, dispar, and Bartlett’s anthias
- Gobies – like yellow watchman, diamond watchman, and Hector’s gobies
- Blennies – like bicolor, algae, and tail spot blennies
- Cardinals – like Banggai and pajama cardinals
- Select wrasses – like possum, Carpenter’s flasher, and fairy wrasses
It should be noted that clownfish may mistake a hammer coral for an anemone, which can cause the coral to retract.
Non-reef-safe species in general would be:
Any invertebrates that are known to snack on fleshier corals should also be avoided, like large hermit crabs and male emerald crabs.
How To Propagate
If you’ve ever propagated a frogspawn or torch coral, then fragging a hammer is straightforward and easy. If you’ve never done either, then no worries, it’s not too hard.
First, you will need tools. An electric saw is most preferred as it provides a clean cut, though bone cutters can work as well. Next, you will want to identify if you have a wall or a branching variety of hammer coral.
This Coral Fragging Kit by DR instruments has everything you need to get started with basic fragging
Branching hammer corals are easier to frag as you just need to separate one branch from the rest of the colony. You can do this by cutting below the flesh and above where the branch begins. This should give enough room to comfortably attach the frag to a plug.
Wall hammers are much more difficult to frag and should only be done with an electric saw for a clean cut. There is no straight method for cutting wall hammers, but it’s ideal to cause as least stress as possible; cut in a section that is relatively straight and where the flesh is thinnest.
All frags should be dipped in iodine or another solution to ensure healthy healing. Keep frag plugs at the bottom of the tank until ready to be moved up to their permanent placements or sold/given away to another hobbyist.
Should You Dip This?
Yes! You should always take the time to dip new corals in a pesticide dip. While this doesn’t guarantee 100% coverage against pests from entering your system, it kills a good amount of problematic species.
For the best results, quarantine the coral in a separate tank for several weeks. This should be plenty of time for pests to rear their ugly heads.
At the very least, it’s strongly recommended to remove the frag plug from the new coral before placing it in your tank. If you would like a base, then you may attach the frag to a new plug and use that in your tank instead.
Possible Pests And Diseases
What are you likely to find on a contaminated hammer coral? While some pests, like algae and various eggs, can be microscopic, there are a few major pests that you don’t want entering your system.
Unfortunately, a dip won’t kill Aiptasia but should cover everything else.
Hammer corals are delicate and stress or injury can quickly lead to rapid tissue necrosis (RTN) which causes the coral to die within a matter of days.
When handling a hammer coral, it’s important to avoid touching the polyp as the flesh is easily damaged. If you need to move the coral for whatever reason, hold it by the skeleton and use gloves as the sweeper tentacles can cause injury to human skin.
How Much Do They Cost?
Because hammer corals are so popular, they have become increasingly available over the past few years. A simple colored hammer coral frag can start at $35-40. Larger colonies with more interesting coloration can cost upwards of a couple of hundred dollars. Remember that hammer corals, especially the branching variety can grow very quickly so it might be worth the wait to let your coral grow on its own!
Is Your’s Dying?
While hammer corals are easy to care for, coral death can come quickly and once it starts, it’s very hard to stop.
A dying hammer coral will be pale or brown, retracted, and sometimes spewing out brown stringy mucus; sometimes, this mucus is just waste that the coral is expelling but paired with the other symptoms, it’s usually the zooxanthellae being pushed out from the coral.
If your coral is already expelling zooxanthellae, then it’s usually too late to reverse the damage. However, observe changes in the tank. Ask yourself these questions:
- Did you recently change the water flow or lighting?
- Did you introduce new fish or invertebrates?
- Did any of your water parameters swing within the last 24 hours?
If you answered ‘yes’ to any of these questions, then this could be the cause of your coral’s decline. Luckily, most of these problems can be fixed if done slowly.
Water Flow And Lighting
If water flow and/or lighting are your problem, slowly return to your previous settings. You may have changed conditions too quickly and it would be best to reattempt at a slower pace. You can adjust your return pumps and your wavemakers as needed. This is why it’s best to work with pumps that can be adjusted on the fly when it comes to keeping a reef tank. There are many DC powered wavemakers these days with great controllers!
If you introduced new livestock, then this can be tricky as we all know how hard it can be to catch fish and invertebrates! Trying to remove them can also cause a good amount of stress, which isn’t ideal for a new addition.
Instead, try covering the coral in a water-permeable container or moving it to quarantine either in or outside of the tank. This should give enough time to see if the new additions were the cause of the problem.
If your water parameters changed over the last day, then this can be difficult to tell if you don’t have a record of your values. However, changes in conditions should also reflect on other corals and livestock. Are all your other corals fully extended with full color?
If yes, then water parameters might not be your problem, or you might just have a sensitive hammer. Regardless, it is best to test all water parameters and perform a water change if you can’t find any other causes. Alkalinity, Nitrate, and Phosphate tends to be the main items to test with LPS coral tanks. Consider investing in quality reef tank test kits to monitor your levels.
Hammer corals are a longtime favorite in the aquarium hobby. These corals sway and interact with the coral, bringing life to large portions of the aquarium. These corals don’t need any specific care and can adjust to a variety of water parameters, water flow rates, and lighting, but stability is key. Hammer corals also don’t need to be fed but will appreciate available nutrients in the water column.
We hope you found this blog post informative and helpful in caring for your new Hammer Coral! If you have any questions or comments, please leave them below. Thank you for visiting!
Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping – both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.