Skip to Content

What Is The Salt Water Centipede In My Aquarium?

After the initial surge of people getting involved in keeping freshwater aquariums a few years back, we have noticed many people moving over to trying their hand at keeping salt water aquariums now.

Although the basic principles are the same as with a freshwater tank, there are a few specific things that you have to factor in and this always results in a number of different questions each month.

One thing that we have seen catching countless people off-guard recently is the “saltwater centipede” with a huge number of people reaching out about it over the last few weeks.

Just like with any tank, there is always a chance of you accidentally adding additional, unintended animals and plants to your tank when you add new fish, substrate, rocks or live plants.

With so many people reaching out and asking various questions about the salt water centipede recently, we wanted to publish our own dedicated article going over everything we see people asking about.

We have added all of the questions to this article to put has much information as possible in one place and you are able to easily navigate the article by the table of contents below.

What Is The Centipede Looking Thing In My Saltwater Tank?

The majority of the salt water centipede creatures in aquariums are just bristle worms and for the most part, they are nothing to worry about.

Some people will intentionally add bristle worms to their salt water tank due to them being great detritus eaters while also helping maintain some other water parameters too.

These salt water centipedes can come in a range of different colors depending on the specific species so even if the one in your tank does not match up with the colors for the bristle worm in the photograph above, there is still a very high chance that it is a bristle worm in your tank.

They tend to grow rapidly too when they have plenty of food and this is why it may seem like all of a sudden you have a huge salt water centipede in your tank when it was less than half its current size only a week ago.

There are a few other creatures that do tend to look like salt water centipedes that could be in your tank but these tend to be very rare.

For the most part, it is safe to presume that you have a birstle worm in your tank unless it looks vastly different to the one in the photograph at the start of this section.

“Bristle worms – Hermodice carunculata” by prilfish is licensed with CC BY 2.0. To view a copy of this license, visit

How Do Bristle Worms Get In Your Tank?

There are a number of ways that bristle worms or “salt water centipedes” are able to get into your tank. Most commonly it is due to adding new live plants, rocks, substrate or in some rare cases fish.

As we touched on above, even if you accidentally added some bristle worm eggs to your tank, they grow at such a rapid pace that it is common for people to think that the salt water centipede has been in their tank for much longer than it actually has.

This can result in people overlooking live plants, rocks, and substrate that they have added to their tank within the last week or two as the entry method for the bristle worm but it usually will have been added to your tank in that way.

This next entry method is unconfirmed but we have seen some people suggest that bristle worm eggs can survive the digestive systems of other animals.

This means if a new fish eats bristle worm eggs before you add it to your tank, it may poop out fertilized, viable bristle worm eggs that can then hatch.

Are Bristle Worms Bad For A Saltwater Tank?

Bristle worms are usually good for a saltwater tank due to the amount of uneaten food, detritus, and carrion that they will eat.

This is able to keep your water cleaner for longer without you having to do as much tank maintenance with some aquarium keepers intentionally adding bristle worms to their tanks for their benefits.

You have to keep in mind that some salt water centipedes are poisonous but it is rare that they will use their poison on their tank mates due to there usually being plenty of risk free food in a saltwater aquarium for it.

The non-poisonous species of bristle worms do tend to be more common anyway so the majority of the time, they are harmless to your fish.

Depending on the type of fish that you keep in your saltwater tank, the bristle worm may end up becoming a part of the food chain itself once it gets large enough.

It is very common for a number of different types of fish to eat bristle worms given the chance.

Can Bristle Worms Hurt You?

Some species of bristle worm can sting you if you touch them due to being poisonous and other species may nip you too but for the most part, bristle worms will not hurt you.

It is very rare that they will harm healthy fish in your tank too but they may see snails and shrimp as a potential food source.

Some people who intentionally add bristle worms to their tanks report that their bristle worms fight on a regular basis.

This is usually just the bristle worms mating rather than actually fighting and they will rarely harm each other unless your tank is very small and there is not much food available.

If you are wanting to remove a salt water centipede from your tank then you should use the methods covered below.

Never try to touch them with your bare hands, especially if you don’t know the specific species of bristle worm that you have in your tank.

How Do You Trap Bristle Worms?

There are a number of different bristle worm traps on the market that you are able to use to remove the salt water centipedes from your aquarium if needed.

A multiple entry trap is usually the best option to go with as it allows bristle worms to enter it from different directions while trapping them once they get inside.

Always read the instructions for your brustle worm trap too as some do require baiting to lure the bristle worms inside while others may not.

We would recommend the SplashNcolor Bristle Worm Trap Box due to its high success rate and low price point but there are a number of other options on the market.

We have seen some people try to make their own DIY bristle worm trap to catch the salt water centipede in their tanks too.

This does generally require more time and effort than just purchasing a commercial trap though and is often not the best route for most people.


That brings our article going over what the salt water centipede in your aquarium is, how to catch it, and if it can hurt you to an end. We hope that you have found our article helpful and that we have been able to help you realise that the bristle worm in your tank may actually offer you some benefits depending on the conditions in your tank with many people choosing to keep them.