Will Clownfish Host Hammer Coral?

Are you considering adding a clownfish to your epic reef display, but are unsure if it will host your hammer coral? 

Clownfish are colorful marine fish that are known for surviving in the ocean by hosting anemones and corals. This relationship is called symbiotic because both parties benefit. The clownfish is protected by the host’s stinging tentacles or polyps by hosting a coral or anemone. In return, the clownfish provides nutrients for the anemone or coral and cleans algae and other detritus such as food waste from their tissues.

Compared to the open ocean, your aquarium provides the perfect predator-free home for clownfish, but give them the chance, and they will host any hammer corals you have. 

This isn’t because your clownfish is attracted to your hammer coral’s beautiful colors like we are, but instead, clownfish have a natural instinct to host your coral. This will even happen if your clownfish is captive-bred, because it is a hereditary trait they cannot change. 

Even though clownfish will naturally host hammer corals, the hosting relationship can cause some issues, which we will discuss in this article.

Do Clownfish Host Hammer Coals?

If there isn’t an anemone to host inside your aquarium, your clownfish is going to swim around and find the next best suitable host, which is likely going to be your hammer coral. 

Often, this is the best of both worlds for reef hobbyists, because you will see your clownfish in its natural habitat without having to buy an anemone, which can cause issues for most corals, particularly aiptasia sea anemones. Also, if you have a small aquarium such as a nano tank, or your aquarium lighting doesn’t meet the requirements for keeping anemones, then it is best to stick to just corals.

Another issue with anemones is that they can move. Except for mushroom corals, corals are sessile, which means they cannot move around the aquarium. When anemones move around aquariums they cause utter chaos (pun intended), blocking the water flow or moving in tiny crevices that make it difficult to remove them, plus you are likely to get stung in your rescue efforts. So, let’s just say, that anemones are not particularly grateful to coral husbandry!

So, without an anemone, clownfish will seek an alternative. 

Which Clownfish Will Host Hammer Corals?

All types of clownfish are capable of hosting anemones and hammer corals. With that said, the Ocellaris clownfish (Amphiprion ocellaris) is one type that really loves to host hammer corals. Therefore, if you are looking for a clownfish specifically to host your hammer coral with good results, these guys are the best bet!

However, the Ocellaris clownfish can still annoy hammer corals, despite their higher success rates in hosting hammer corals. So, always monitor your hammer coral’s health.

Can Two Clownfish Host Hammer Coral?

They absolutely can! If you have ever seen clownfish in the wild, then you probably noticed they often live in pairs, if not a whole family. This is because clownfish live in groups with a dominant female and a smaller male who she will pair with for life. 

The rest of the group includes non-breeding females who are there in case the female dies. If she dies, one of the males will grow larger and change sex to become the next dominant female – insane, I know! 

But back to your hammer coral…

Because clownfish like to pair up, you should introduce two at the same time to prevent conflict, particularly if you only have one potential coral for the clownfish to host – you wouldn’t want a stranger to walk into your home and expect to share it.

Tips For Encouraging Clownfish To Host Hammer Corals

While clownfish are pretty good at seeking hosts in aquariums, they also have different personalities and minds of their own, so, you need to be patient until it has found a suitable candidate to host. 

That being said, there are a few things you can try to encourage your clownfish to host your hammer coral. 

The most important factor is size. Clownfish will not host a small hammer coral, because they require a large coral colony to protect them, therefore your hammer coral should be bigger than your clownfish so that they can swim and hide inside the coral. 

Your hammer coral should also go inside your aquarium first so that it has time to acclimate and establish itself. If you already have a clownfish, temporarily move it into another reef tank until your hammer coral is ready to check-in a guest. 

Once your hammer coral is ready for its new resident, get a clear, plastic tube that is wide enough for your clownfish to fit inside – you don’t want a Finding Nemo moment! 

Next, place one end of the tube by your hammer coral and gently place your clownfish inside the other end, so it can easily swim and find the coral. As mentioned, clownfish have a mind of their own, so use a net to gently guide your clownfish toward the hammer coral. If your clownfish is not playing ball, and it is ignoring your hammer, give it a few weeks to see if it hosts – it may just not be love at first sight, so give it some time. 

Over the next few weeks try guiding the clownfish again towards your hammer coral to encourage it, or you can try the tube method again if you haven’t been successful with the net. 

If after a few weeks, you still have no luck, start from the beginning, but introduce them to an aquarium that only contains your hammer coral and clownfish, so that there are no distractions. 

If all fails, lastly, you can try moving your hammer coral to an area where your clownfish likes to hang out. However, if you move your hammer coral, make sure the new location meets your coral’s water flow and lighting requirements. Remember that hammer corals require moderate lighting (PAR 80-150) and moderate non-linear water flow to thrive.

How Do Clownfish Behave When They Host Hammer Corals?

Many reef hobbyists worry about adding clownfish to aquariums because of bad behavior, however, not all clownfish will cause chaos to corals. 

In the beginning, you may notice your clownfish acting strange toward your hammer coral, but do not worry, this is normal. Preparation is an important part of your clownfish hosting your hammer coral. 

Preparation includes your clownfish rubbing against your hammer coral’s polyps and/or slapping it with its tail. This behavior isn’t for fun, but it is a crucial part of protecting the fish. Clownfish do this to coat themselves in a protective mucus that your hammer coral produces, which protects the clownfish from being stung by other corals and anemones. 

During this time, your hammer coral may retract its polyps because it finds this behavior too aggressive, especially if your clownfish also starts nipping the tips of your hammer coral’s polyps. Your clownfish may do this to build up their resistance to your hammer coral’s toxin, not just for fun, like butterflyfish. 

Possible Issues When Clownfish Host Hammer Corals

Anemones are the best hosts for clownfish because corals like your hammer coral are not used to having colorful clownfish nipping their polyps or rubbing up against them. 

Sometimes, hammer corals find clownfish too aggressive, causing them to close up. If your hammer coral retracts its polyps for a long time, it will not receive enough lighting, and your coral will also be unable to catch food from the water column.

Another issue, when your hammer coral retracts its polyps, is your clownfish may leave your hammer coral until it extends again, and in some cases, your clownfish may abandon hosting your hammer coral for good. The two of them may continuously do this until your hammer coral finally tolerates its new guest. This small conflict may make your clownfish more gentle towards the hammer coral, and the hammer coral might become more tolerant toward the clownfish. 

If your clownfish seem to annoy your hammer coral in any way, monitor your coral’s health. If your hammer coral’s health goes downhill, remove it, treat it with a coral dip like iodine or CoralRX if it’s damaged, and give it time to recover before placing it back inside the aquarium.

Can Hammer Corals Harm Clownfish?

Hammer corals pose no threat to clownfish despite their tentacles densely packed with stinging cells called nematocyts. Clownfish wouldn’t host a hammer coral if they feared it. 

As clownfish have thick bodies with a mucus layer, they can tolerate being stung by your hammer coral; this is how clownfish can host anemones. So, you have nothing to worry about regarding your clownfish’s health. 

Will Clownfish Also Host Torch Corals?

If your hammer coral is not a suitable host, your clownfish may look for a more worthy home. If you have any torch corals, and you don’t have any anemones, then your clownfish may choose to host a torch. 

Unfortunately, when clownfish try to host a torch coral, it doesn’t always end well… 

Hobbyists that have experienced this, find that the clownfish will kill the torch coral from too much damage. The clownfish do not intend on killing the torch coral, but by nibbling their sensitive polyps, the clownfish accidentally kills the LPS.

Because of this, it is not recommended to add a torch coral as a hammer coral or anemone substitute. However, not every hobbyist’s experience has ended up in a disaster, many people have been successful, but it is much riskier than the other options.

Clownfish hosting torch coral


Hosting is a natural process in a clownfish’s life, in fact, it is one of their hereditary traits. If there are no anemones to host inside your aquarium, clownfish will have no problem finding an alternative. 

When clownfish host a hammer coral, it will rub up against the polyps and occasionally nip to build up a tolerance to the stinging cells, covering it in protective mucus during the process. Often, hammer corals find this too aggressive, and they withdraw their polyps. 

This doesn’t mean your hammer coral has rejected the clownfish, it just means it needs some time to build up a solid relationship. On average, it usually takes a few weeks for your hammer coral to accept the clownfish as a guest, and once they accept each other, you will not only have a happy clownfish and coral, but you will also have an epic coral reef display!

  • 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.

    http://reeftankadvisor.com reeftankroy@gmail.com Lee Roy

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