Hammer Corals: The Hard-Hitting Beauties of the Reef World

| Updated: July 13, 2023
Rainbow Hammer Coral

Hey, reefers! Let’s talk about one of the most amazing corals you can have in your reef tank: the hammer coral. If you are looking for a coral that will wow you and your guests with its stunning colors, shapes, and movement, you can’t go wrong with the hammer coral. This coral is a true gem of the reef, and I’m going to tell you everything you need to know about it in this article.

The hammer coral ( Euphyllia Ancora or Euphyllia Paraancora for the branching type) is a type of LPS (large polyp stony) coral that belongs to the Caryophyllidae family. It gets its name from its hammer or anchor-shaped polyps that extend from its stony base. These polyps can come in different forms: T-shaped, curved, or round. They can also come in different colors: green, blue, purple, orange, pink, or brown. Some hammer corals have contrasting colors between their tentacles and their polyp tips, creating a fluorescent effect under actinic lighting.

Hammer Coral (Euphyllia ancora) grows on a reef in Indonesia.
Credit: Ethan Daniels/Stocktrek Images/Gettyimages

The hammer coral is native to the tropical waters of the Indo-Pacific region, where it can be found on shallow reefs up to 130 feet deep. It is a popular coral among reef hobbyists because of its beauty, hardiness, and adaptability. They can grow in different lighting and flow conditions, and it can also be propagated easily by fragging. However, they are not the most beginner-friendly coral, as it requires stable water parameters, moderate care level, and supplemental feeding. Although they are certainly not the most difficult coral either. They can be aggressive and sting other corals with their sweeper tentacles, so it needs plenty of space and compatible tank mates.

The hammer coral is one of my favorite corals of all time, and I’m sure you will love it too, once you see it in your tank. It is a coral that will add a lot of personality and movement to your reef and make you proud of your coral-keeping skills. In this article, I will show you how to choose, care for, frag, and enjoy your hammer coral. So let’s get started!

Hammer Coral Care

Now that you know what hammer corals are and why they are so awesome, let’s talk about how to care for them in your reef tank. Hammer corals are not the easiest corals to keep, but they are not the hardest either. They are somewhere in the middle, requiring some attention and dedication from you but rewarding you with their beauty and growth. Here are some of the key aspects of hammer coral care that you need to consider:


Hammer corals can be placed anywhere from the bottom to the middle of your tank as long as they get enough light and flow. However, you need to be careful about their neighbors, as hammer corals can be aggressive and sting other corals with their sweeper tentacles. You should leave at least 5 inches of space between your hammer coral and any other coral that is not from the same family (Euphyllia). The best tank mates for hammer corals are torch corals, frogspawn corals, and other hammer corals. You can even create a stunning Euphyllia garden by mixing different colors and shapes of these corals.


Hammer corals are photosynthetic animals and need light to survive. You can’t keep corals without good lighting. Invest in a quality lighting system now to help keep problems to a minimum. However, they are quite adaptable corals in terms of lighting. Just make sure that you acclimate them slowly to your lighting conditions, and avoid placing them under direct or intense light that can burn their delicate polyps. A moderate light intensity of around 80-150 PAR is ideal for hammer corals.

Water Quality

Reef keeping success majorly depends on water parameters. High-quality water ensures your corals are bright and healthy. On the other hand, poor quality can cause a lot of problems to fix: from bacteria and algae to bleaching and death. The key factors that affect water quality for hammer corals are salinity, pH, temperature, calcium, alkalinity, nitrate, phosphate, and magnesium. You should aim for the following values for these parameters:

Common NameHammer Coral
Scientific NameEuphyllia Ancora or Euphyllia Paraancora (branching)
Ease of CareModerate
Lighting (PAR)80-150 PAR
Water FlowMedium
Alkalinity8-12 dKH

To maintain these values, you need to test your water regularly with a reliable test kit or monitor, perform frequent water changes with a high-quality salt mix, use a protein skimmer and a refugium to remove excess nutrients and organic waste, and supplement calcium, alkalinity, and magnesium as needed with kalkwasser or a two-part solution.


Hammer corals are not only photosynthetic but also heterotrophic, meaning that they can eat food particles from the water column. Feeding your hammer coral will boost its growth, coloration, and health. You can feed your hammer coral once or twice a week with foods such as mysis shrimp, brine shrimp, krill, or coral pellets. To feed your hammer coral, you can use a turkey baster or a pipette to target feed each polyp individually, or you can broadcast feed the whole tank and let the hammer coral catch what it can. Either way, make sure to turn off your pumps and powerheads during feeding time to prevent the food from being blown away.

If you follow these guidelines for hammer coral care, you will have a happy and healthy coral that will reward you with its beauty and growth for years to come. Hammer corals are not only stunning but also fascinating creatures that can add a lot of personality and movement to your reef tank.

Fragging Hammer Coral

One of the coolest things about hammer corals is that you can propagate them in your own tank. Propagating, or fragging, corals is a great way to increase your coral collection, share your corals with other reefers, or even sell them for some extra cash. Plus, it’s a lot of fun and very rewarding to see your frags grow into new colonies. Hammer corals are relatively easy to frag, especially if you have the branching variety. Here are some of the steps and tips for fragging hammer corals:

  1. Choose a healthy and mature hammer coral colony that has at least 5-10 polyps. Make sure the coral is well-fed and has good coloration and extension. Avoid fragging stressed or diseased corals, as they may not heal well or survive.
  2. Prepare your tools and materials. You will need a sharp pair of bone cutters or coral scissors, a small container with tank water, some epoxy putty or super glue gel, some frag plugs or small pieces of live rock, and some rubber bands or fishing line. You will also need a separate tank or container with a heater, a powerhead, and some saltwater for holding your frags until they heal.
  3. Cut off a branch or a piece of the wall of your hammer coral with the bone cutters, dremel, or coral saw. Try to make a clean cut between the heads, avoiding cutting through any flesh. You can make as many frags as there are heads, providing you have the angle needed to make the cut. Place the frags in the container with tank water.
  4. Attach each frag to a frag plug or a piece of live rock with some epoxy putty or super glue gel. Make sure the frag is secure and stable on the plug or rock.
  5. Give the cut frags a nice iodine dip to help them heal and prevent disease/infection.
  6. Place the frags in a separate tank or container with a heater, a powerhead, and some saltwater. Keep them in a low to moderate light and flow area for at least a week or two until they heal and attach to their new base. After a day or two you can try to feed them lightly, which may help speed up their recovery.
  7. Once the frags are healed and attached, you can move them to your main tank, give them away, or sell them to other reefers. Enjoy your new hammer coral colonies!

Fragging hammer corals is not only easy but also beneficial for your corals and your tank. By fragging your hammer corals, you can reduce their aggression and prevent them from overgrowing your tank. You can also create more diversity and beauty in your reef by mixing different colors and shapes of hammer corals. And you can share your passion and hobby with others by spreading these amazing corals around.

Pests and Diseases That Affect Hammer Corals

Unfortunately, as much as we love our hammer corals, they are not immune to the threats that lurk in our tanks. Sometimes, despite our best efforts, things can go wrong, and our corals can get sick or infested. But don’t worry because I’m going to tell you how to prevent, identify, and treat some of the most common problems with hammer corals.

Brown Jelly Disease (BJD)

One of the most dreaded diseases that can affect hammer corals is brown jelly disease. This is a bacterial infection that causes a brown, slimy substance to cover the coral polyps and tissue. It can spread quickly and kill the coral in a matter of days. The causes of brown jelly disease are not fully understood, but it may be related to poor water quality, stress, physical damage, or low salinity.

To prevent brown jelly disease, you need to keep your water parameters stable and pristine, quarantine new corals before adding them to your tank, dip your corals in coral-safe solutions to remove pests and pathogens, and avoid injuring your corals during handling or fragging. 

Treating brown jelly disease is a bit of a misconception. There is no proven method (yet) of curing BJD. The currently recommended method is to remove the affected coral from your tank as soon as possible, cut off the infected head(s) with any of the tools I mentioned for fragging, dip the coral in an iodine solution for 15 minutes, and place it in a separate tank or container with clean water and antibiotics until it recovers.

EEFW (Euphyllia Eating Flatworm)

Another common problem with hammer corals is EEFWs (Euphyllia Eating Flatworms). These are pesky little parasitic worms that can cover and suffocate the coral polyps. They can also release toxins when disturbed or killed, which can harm other corals in your tank. Flatworms can be introduced by new corals or live rock that are not properly dipped or quarantined.

To prevent flatworms, you need to follow the same steps as acclimating any new coral: quarantine and dip new corals and live rock and inspect your corals regularly for signs of infestation. To treat flatworms, you need to remove the affected coral from your tank, dip it in a flatworm-specific solution for 10 minutes, rinse it with clean water, and place it back in your tank. You may also need to treat your whole tank with a flatworm-specific medication if the infestation is severe.

My personal preference when it comes to dipping corals for pests is CoralRX. It’s extremely effective for almost all pests, including Flatworms. Also easily purchasable from Amazon. I hate waiting for shipping like most people do, so this is always a huge plus.

Vermetid Snails

A third common problem with hammer corals is vermetid snails. These are snails that produce mucus nets that can trap and irritate the coral polyps. They can also compete with the coral for food and space. Vermetid snails can be introduced by new corals or live rock that are not properly dipped or quarantined. To prevent vermetid snails, you need to inspect any new frag or rock for their hard tube. To treat vermetid snails, you can manually remove them from your coral or live rock with tweezers or a toothpick. You can also use super glue gel or epoxy putty to seal their tubes shut.

These are some of the most common pests and diseases that can affect your hammer coral. However, there may be other problems that are less common or more difficult to diagnose. If you notice any unusual signs or symptoms on your hammer coral, such as bleaching, tissue recession, swelling, lesions, or spots, you should act quickly and seek help from an expert or a reputable forum. The sooner you identify and treat the problem, the better chance you have of saving your coral.

Hammer corals are amazing creatures that deserve our care and attention. By following these tips and guidelines, you can prevent most of the pests and diseases that can harm them. And by being vigilant and proactive, you can treat any problems that may arise before they become fatal. Remember: an ounce of prevention is worth a pound of cure!

Gold Hammer Coral
Credit: Voislav Kolevski / 500px/Gettyimages


Well, that’s it for this article on hammer corals. I hope you learned something new and useful about these awesome corals. Hammer corals are truly one of the best LPS corals you can have in your reef tank. They are stunning, hardy, and easy to propagate. They will add a lot of movement and color to your reef and make you proud of your coral-keeping skills.

If you are interested in getting a hammer coral for your tank, you can check out some of the online vendors that I recommend below. They have some of the best quality and variety of hammer corals available, and they will ship them to you safely and quickly. Just make sure to follow the guidelines and tips that I shared with you in this article, and you will have no problem keeping your hammer coral happy and healthy.

If you have any questions or comments about hammer corals, feel free to leave them below. I would love to hear from you and see some pictures of your hammer coral colonies. And if you enjoyed this article, please share it with your fellow reefers and subscribe to my newsletter for more articles like this. Thank you for reading, and happy reefing! 😊

Vendor resources:

Queen Anne’s Corals

Q: How do I choose a hammer coral for my tank?

A: Look for a healthy and mature specimen that has good coloration and polyp extension, as well as no signs of damage or disease. Avoid buying wild-collected corals, as they may not adapt well to captivity and may harm the natural reefs. Buy from reputable vendors that offer aquacultured or captive-bred corals instead.

Q: Where do I place a hammer coral in my tank?

A: Anywhere from the bottom to the middle of your tank, as long as it gets enough light and flow. But not too much light and flow because that can stress it out. And not too close to other corals because it can sting them. And not too far from other corals because it can get lonely. You get the idea.

Q: How do I make my hammer coral grow faster?

A: Feed it well, supplement it with calcium and alkalinity, and keep your water parameters stable and pristine. Patience and stability is the golden rule here.

Q: What are the common problems with hammer corals?

A: Some of the common problems with hammer corals are bleaching, tissue recession, brown jelly disease, flatworms, and vermetid snails.

Q: Can I keep a clownfish with a hammer coral?

A: Yes, you can. Some clownfish may choose to host a hammer coral instead of an anemone. This can be beneficial for both the clownfish and the coral, as they provide protection and nutrients for each other. However, some clownfish may be too rough or aggressive with the coral polyps, causing them to retract or get damaged. If this happens, you may need to separate them or provide an alternative host for the clownfish.

Shane Elliot Author Image
Shane Elliot

Shane Elliot is a pet lover and a coral enthusiast. He has been keeping saltwater aquariums for over ten years and enjoys sharing his knowledge and expertise with other hobbyists. He writes about coral care, fish compatibility, aquarium equipment, and more. He also covers topics related to other animals, such as dogs, cats, horses, and reptiles. Shane works as a freelance writer and editor when his menagerie of pets allows it.

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