Do Hammer Corals Sting?

Are you worried that your hammer coral can sting your other corals or even your hand if you were to accidentally brush up against or handle them? 

After anemones, large polyp stony (LPS) corals have the most powerful sting out of all aquarium corals, and because of this, these types of corals are considered aggressive – but do hammer corals sting?

Can Hammer Corals sting?

Large polyp stony corals like hammer corals have long sweeper tentacles that can extend and sting anything in their path. Inside the hammer coral’s tentacles and outer tissues, are stinging cells called nematocysts. You may already be familiar with these if you have ever been stung by a jellyfish. 

So, because jellyfish and corals are close cousins (both belonging to the phylum cnidaria), many hobbyists worry that touching hammer corals will leave them or their corals with the same outcome. 

Will Hammer Corals Sting Other Corals?

Given the chance, your hammer coral will sting other corals, but whether the other coral becomes damaged, will depend on what coral your hammer coral has taken a swipe at. 

Your hammer coral is an LPS coral, so it can extend its tentacles as far as they will go. The tentacles contain stinging cells that can sting, burn, and damage or kill other corals that get in the way. During this process, chemicals are also released into the aquarium, which can affect your aquarium’s water chemistry. This is why, when keeping aggressive corals like hammers, you should run carbon.

That being said, hammer corals are not usually aggressive to other Euphyllia corals like torches, grape corals, and frogspawns. Because of this, LPS lovers will often keep multiple Euphyllia corals in the same reef tank. 

But, when placing your hammer coral next to non-aggressive corals, you should leave at least 6 inches to allow plenty of space for growth and to reduce possible chemical warfare. 

Will My Hammer Coral Sting Me?

As hammer corals can sting other corals, many reef hobbyists, particularly beginner aquarists become worried about their safety when keeping hammer corals. 

The good news is, very few coral stings are strong enough to penetrate the upper epidermis layer of human skin, but your hammer coral will cover you in their mucus layer, should you touch it. 

Hammer corals coat themselves in a mucus layer to protect themselves from desiccation. Therefore, if you are sensitive to irritants, then the mucus may cause an allergic reaction, a burning sensation, and/or welts on the hand. 

For that reason, it is always best to wear gloves if you need to handle your hammer coral. Medical-grade rubber gloves with a minimum thickness of 1 mm create a perfect barrier between you and your coral. 

But, one thing that I must warn you about is open wounds… 

You must NEVER touch any corals with bare hands if you have any open wounds. An open wound makes the perfect pathway for coral toxins to enter the dermis layer where your blood vessels, hair follicles, and nerve endings are found.

If your hammer coral stings any open wounds, you will need to treat the area as soon as possible!

How To Treat Coral Stings

The second an open wound comes into contact with coral toxins, apply a cool compress and hydrocortisone cream. If the area becomes itchy, take oral histamines, and if you still experience itchiness or burning after 24 to 36 hours, go and seek medical assistance right away.

Most doctors will prescribe antibiotic medication to prevent infections.

What To Do When Handling Hammer Corals?

As mentioned, you should wear gloves when handling your hammer coral. But, the main issue when handling corals is actually the damage we can cause. 

If you need to change your hammer coral’s placement or remove it from the aquarium, extra caution should be made so that you don’t damage your coral’s delicate tentacles. Keeping contact to a minimum is also important, your hammer coral is not a cat or dog, therefore it does not require you to pet or touch it to be happy; corals are most happy when left alone in stable conditions. 

But, if you have to touch it, then pick your hammer coral up from the base and move it gently in the water to prevent tearing its tissues. 

It is also crucial you wash your hands before placing them into the aquarium and touch any corals to prevent contaminants from entering the water. 


Hammer corals are part of the LPS group, notorious for their long sweeper tentacles that contain stinging cells called nematocysts. 

With one large swipe, your hammer coral can throw quite a powerful punch at neighboring corals that get in their way. This is why hammer corals should be placed at least 6 inches apart from corals that are not within the Euphyllia group. 
If you need to handle or touch your coral, then you shouldn’t feel anything unless you are sensitive to irritants. However, it is recommended to wear gloves – it is always better to be safe than sorry!

  • 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.

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