Bristle Worm – Good or Bad?

Bristle Worm white sand

Many people use bristle worms in their aquariums, but there is a lot to learn about these aquatic organisms. 

If you are already keeping fish or want to set up one, you’ll definitely be interested in these particular worms.

Physical Traits

Bristle worms can grow up to an incredible 24 inches, though a majority of them don’t get any longer than six inches or so. They are, however, very slim and are capable of slithering their way into even the tiniest openings.

These worms have segmented bodies that that each has a set of parapodia. A majority of these worms have sensory palps, antennae, and a head with eyes. There are thousands of different types, so you will need to keep that in mind.

Errant bristle worms swim around and crawl, while sedentary worms tend to burrow and cannot move around as smoothly.

How do Bristle Worms get in Aquariums?

Bristle worms typically get into saltwater aquariums when someone puts new plants, caves, rocks or other things in them. The worms are already on these items from the start, and it doesn’t take long for them to grow.

It is therefore important that you make a point of thoroughly rinsing out anything you buy before putting it in your tank. This will go a long way towards preventing this issue.

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Nature’s Cleaners

One of the reasons that a lot of fish keepers love certain bristle worms is because they help to keep their tanks clean. These worms scavenge for food in an aquarium, eating leftover fish food or anything that has started to rot. They will even eat fish after they have died.

Since these worms are able to squeeze into very tight spaces, they are very thorough cleaners. This can certainly reduce the amount of time that you need to spend cleaning your aquarium each week.

You will find that some species of bristle worms are just as good at keeping a tank clean as the average starfish or snail.

Bristle Worm in corals

Separating the Good from the Bad

It is important that you are able to distinguish the “good” bristle worms from the “bad” ones. This will allow you to preserve the health and well-being of your aquatic pets. While most of the bristle worms that appear in saltwater tanks won’t do any harm, this is not always true.

Fireworms can be very harmful to the fish in your tank. They are known for being very aggressive with even large fish, and they can destroy coral. You can recognize these worms by their dark red coloration that appears almost brown. All fireworms are bristle worms, but the opposite is not true.

Bearded fireworms usually grow to be around six inches, but they can be as long as 12 inches. These worms have red bristles with some red, gray, green or even yellow coloration.

The good variety of bristle worms typically have bristle tufts that are spaced evenly down their sides. They also have white bristles that appear very bright. These worms are usually quite bright as well.

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Handling Bristle Worms

When you are handling bristle worms, it is important to wear gloves. These worms can sting with their little spikes. While they don’t release any poison or venom, a single sting can hurt quite a bit.

If you happen to get stung by a bristle worm, you’ll want to put a piece of duct tape on the area and pull it off quickly to remove the spike. You should then wash the wound and apply antibiotic ointment just to be safe. This will drastically reduce the chances of infection.

Removing Bristle Worms from your Tank

If you have bristle worms in your aquarium that you want to remove, there are a number of options to consider. Some of these methods can be more effective than others, depending on the nature of your situation.

1. Put in a Predator

There are numerous fish and other aquatic organisms that could take care of your bristle worm problem very quickly. The Arrow Crab, Wrasse, and Coral Banded Shrimp are just a few options to consider.

Pufferfish are also generally a good choice when you have a problem with bristle worms in your tank. This is by far one of the easiest and most effective ways to resolve this issue.

2. Set a Trap

You can also try setting a trap for the bristle worms that have invaded your aquarium. These traps are available at fish stores as well as online. You may want to try making your own trap at home to save some money. 

All you need is an empty plastic bottle. Just cut the top off the bottle and flip it around to make a funnel. Put some tasty food that the worms won’t be able to resist inside of it. Some dead leaves can be very enticing to these worms.

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Bristle Worm portrait e1580753785716

3. Take them out Manually

There is always the option of taking the bristle worms out by hand, but it can be tricky. Make sure that you wear gloves and use some tweezers. This will make it easier to get these slippery scavengers.


  • Bristle worms get into an aquarium when someone puts something in it without rinsing it off first.
  • These worms are often on plants, rocks and other items that people put in fish tanks.
  • There are some “good” bristle worms that can help keep your aquarium clean, which can be very helpful.
  • Other types of bristle worms can do a lot of damage to reefs and fish in an aquarium.
  • If you ever need to handle any of these worms, it is important to wear gloves, as they do have shark spikes.
  • One of the best ways to get rid of these worms is to put in a predator that will eat them.
  • You can also try buying or making a trap that to catch these worms inside your tank.
  • If you are going to remove the bristle worms by hand, make sure to wear gloves and use tweezers.