Is My Hammer Coral Splitting?

If you are a newbie hobbyist, you may be concerned about witnessing your hammer coral tearing into two, but if it is in the middle of splitting, then there is nothing to worry about. 

In fact, you should be proud that your good husbandry skills have led to your hammer coral naturally splitting!

Why Do Corals Split?

Corals split as a form of asexual reproduction. While most corals partake in mass spawning events in the wild by releasing eggs and sperm into the water, inside your aquarium, you are more likely to witness split spawning. 

When a coral splits, it divides into two, separating and growing in separate directions to form new coral polyp heads. If you witness this inside your aquarium, it is pretty epic!

How To Know If My Hammer Coral Is Splitting?

Once your hammer coral has grown its skeleton, it will be ready to start the splitting process, which is super exciting. 

As your hammer coral splits, it usually occurs directly down the center of its mouth. As the two heads branch off to form two separate hammer colonies, you may see your hammer coral slightly shrinking, but do not worry, as this is normal!

When your hammer coral is splitting, it should look happy and healthy, showing no signs of distress, such as closing up for a long time. During the splitting process, your hammer coral’s tissue may also appear thinner, this should not cause any concern unless your hammer coral’s tissues start receding or it starts exposing its bare skeleton. 

What To Do When Your Hammer Coral Is Splitting?

As your hammer coral splits, there is not much to do, other than be patient and maintain tank stability. In particular, focus on maintaining stable calcium and alkalinity levels to help your hammer coral split and branch out bigger. 

Creating A Stable Environment

  • Provide moderate water flow
  • Provide moderate lighting (PAR 80-150)
  • Performing 5-10% water changes every 1-2 weeks
  • Maintaining the following water levels: Temperature: 72° – 78 °F, pH: 8.1 – 8.3, salinity: 1.024 – 1.026, alkalinity: 8 – 12 dKH, nitrates: <10 ppm, phosphates: <0.10 ppm, calcium: 350 – 450 ppm, magnesium: 1200 – 1350

In addition to keeping the above conditions stable, you can feed your hammer coral to give it an extra boost and strength in recovery. Something like mysis or brine shrimp will make the perfect meaty treat for your hammer coral. 

How Long Does It Take For Hammer Corals To Split?

When your hammer coral splits, you cannot expect it to be an overnight process. 

Remember that every coral is different, and each has its own personality like us. Some hammer corals may take a few days to successfully split, and others can take as long as two months to complete the split spawning process.

How To Manually Split Your Hammer Coral

If your hammer coral has fully acclimated to your aquarium, and it shows no signs of splitting for a while, then you can lend it a hand. You can manually split your hammer coral in a process known as fragging. 

Fragging is usually very easy, but, this depends on whether you have a branching hammer coral or a wall hammer coral. 

Generally, fragging a branching hammer coral is easier, and usually, you have a higher chance of having a successful outcome. However, this doesn’t mean that fragging a wall hammer is impossible, but it does require a little more patience and a different technique.

How To Frag Branching Hammers?

  • Choose a healthy part of the hammer coral. 
  • Break off one of the branches, or use a knife or a set of pliers to cut off a section.
  • Dip your coral frag into an iodine solution to prevent any infections. 
  • Using reef-safe IC gel glue or putty, take your branching hammer frag and glue it to a frag plug or live rock. 
  • Once the coral frag is secure, place it on the sandbed to allow time to heal. 

How To Frag Wall Hammers?

  • Follow the above steps, but when fragging wall hammer corals, you need to use a Dremel tool. 
  • You will also need to wait until your wall hammer retracts its polyps, which allows you to see where you are cutting. 
  • Using the Dremel tool, cut directly through the base. 
  • Next, dip your wall hammer coral in an iodine solution.
  • Glue your wall hammer coral to a live rock or frag plug the same way you would with a branching variety. However, you can reshape wall hammer corals, so get your artistic hands ready!
  • Finally, place your wall hammer coral at the bottom of the tank to heal.

Hammer Coral Splitting VS Tearing

Sometimes hobbyists, particularly beginner reefers, confuse hammer corals splitting with tearing. If your hammer coral is in a high-flow area, you risk tearing its polyps. 

Before a coral starts to tear, it will usually close its polyps to protect them, but if your hammer coral continues to get blasted with high flow, you risk a tissue rupture. 

Once your hammer coral tears, bacterial infections (like the deadly brown jelly disease) will soon finish off your coral if you do not treat it. Recovery of bacterial infections will depend on how significant the damage is, and your aquarium’s tank parameters. 


I’m sure you would agree that every coral enthusiast’s goal is to experience their coral successfully splitting. 

When a hammer coral splits, it will divide itself directly down the middle into two coral heads. During this time, be patient and keep the conditions stable. Soon you will have two beautiful hammer corals to look after and enjoy!

Check out our guide for more hammer coral care information!

  • Roy Lee

    I have an unhealthy obsession with reef keeping and maintaining successful tanks. If you haven't noticed from the website, I love everything related to saltwater tanks like coral, fish, and everything else in between.

Leave a Comment