What the heck is this

[Paulie069]

I was cleaning my rocks yesterday and I had a rock in a container to rinse off real quick and all of a sudden this morning I noticed at the bottom of the container there was this little freaking worm with black eyes and a red tail never saw anything like it

 

[ScottR]

Bristleworm

 

[TheShrimpNibbler]

Bristle worm. It’s harmless, and you’ve probably got a lot more in your tank

 

[DeniseAndy]

Just try not to pick it up with fingers. Can hurt. Not as bad as fire worm though. Ouch, Those are rough.

 

[hankacrank]

Looks like a common, pink bristle worm. There is controversy regarding whether they belong in your tank. Most people endorse that they are the best clean-up-crew member you can have. They are very good about eating leftover fish food that can lead to contamination spikes. They also are able to access detritus in hard-to-reach places that other CUC cannot get to.

Controversial: there is a myth perpetuated that once they grow "large enough", they can eat/kill your fish. However, I have never been able to find a photo/proof on these forums of a bristle worm attacking/eating a fish while it is still alive. Of course they will eat inverts or fish that have died of natural/other causes. But they have not been proven to be a true predator.

Fire bristle worms on the other hand are a different story, supposedly.

 

[Paulie069]

Looks like a common, pink bristle worm. There is controversy regarding whether they belong in your tank. Most people endorse that they are the best clean-up-crew member you can have. They are very good about eating leftover fish food that can lead to contamination spikes. They also are able to access detritus in hard-to-reach places that other CUC cannot get to.

Controversial: there is a myth perpetuated that once they grow "large enough", they can eat/kill your fish. However, I have never been able to find a photo/proof on these forums of a bristle worm attacking/eating a fish while it is still alive. Of course they will eat inverts or fish that have died of natural/other causes. But they have not been proven to be a true predator.

Fire bristle worms on the other hand are a different story, supposedly.

So do I leave him or toss him, I’m not one to take chances with my tank, if there’s any inkling it might be a bad thing then I’m toilet it goes

 

[DeniseAndy]

Does not matter. You have one, you have many. Do as you want. They are always being lost in my socks or when I clean tanks and rocks. Still manage to multiply.

 

[hankacrank]

So do I leave him or toss him, I’m not one to take chances with my tank, if there’s any inkling it might be a bad thing then I’m toilet it goes

Does not matter. You have one, you have many. Do as you want. They are always being lost in my socks or when I clean tanks and rocks. Still manage to multiply.

I agree exactly with what @DeniseAndy said. You can toss it if you want, but if it's reached that size already (he appears 3-5" long if I'm guessing correctly), then you've probably got many in your live rock/sand at this point. The young ones will appear only several millimeters long, are closer to white in color, and move incredibly fast over the surface of rock and sand. If you use a flashlight 30-60 minutes after your photo period, you will see them flying across rocks.

Bristle worms typically come out en masse 30-60 minutes after your photo-period, and it's your best opportunity to catch larger worms with forceps.

You can toss him if you are worried, but I would not go crazy getting rid of them with traps, etc. The first time I ever found one, I freaked out and told one of my aquarium management contacts about it, and he told me to leave them alone. "Do not dispose of them". He manages many high end home and business tanks in the city of Chicago. He says that he always leaves bristle worms in the tanks because they are part of nature's "ecosystem balancing act".

Another reefer here that I've talked to a lot, @mfollen, is of the school of thought that he doesn't like to mess with any foreign invaders that he did not place into his tank. He started fully from dry rock so he has absolutely zero bristle worms in his tank and it is flourishing.

Lastly, a wrasse of some sort will keep them in check. Or if your tank is smaller, watchman goby's have been known to eat smaller/baby bristle worms.

I don't exactly want to endorse adding fish to control pests as that is also controversial. I only mention this in case you've been considering these species anyway and this might help steer you in their direction.

Again, it's up to you what you choose to do.

 

[Paulie069]

I agree exactly with what @DeniseAndy said. You can toss it if you want, but if it's reached that size already (he appears 3-5" long if I'm guessing correctly), then you've probably got many in your live rock/sand at this point. The young ones will appear only several millimeters long, are closer to white in color, and move incredibly fast over the surface of rock and sand. If you use a flashlight 30-60 minutes after your photo period, you will see them flying across rocks.

Bristle worms typically come out en masse 30-60 minutes after your photo-period, and it's your best opportunity to catch larger worms with forceps.

You can toss him if you are worried, but I would not go crazy getting rid of them with traps, etc. The first time I ever found one, I freaked out and told one of my aquarium management contacts about it, and he told me to leave them alone. "Do not dispose of them". He manages many high end home and business tanks in the city of Chicago. He says that he always leaves bristle worms in the tanks because they are part of nature's "ecosystem balancing act".

Another reefer here that I've talked to a lot, @mfollen, is of the school of thought that he doesn't like to mess with any foreign invaders that he did not place into his tank. He started fully from dry rock so he has absolutely zero bristle worms in his tank and it is flourishing.

Lastly, a wrasse of some sort will keep them in check. Or if your tank is smaller, watchman goby's have been known to eat smaller/baby bristle worms.

I don't exactly want to endorse adding fish to control pests as that is also controversial. I only mention this in case you've been considering these species anyway and this might help steer you in their direction.

Again, it's up to you what you choose to do.

It’s actually very tiny Maybe an eighth of an inch long but from what I’ve read it seems to be OK for my tank and I’ve never had any problems with my seahorses or Fish since I started I just wonder where he came from

 

[Robert Binz]

Looks like a common, pink bristle worm. There is controversy regarding whether they belong in your tank. Most people endorse that they are the best clean-up-crew member you can have. They are very good about eating leftover fish food that can lead to contamination spikes. They also are able to access detritus in hard-to-reach places that other CUC cannot get to.

Controversial: there is a myth perpetuated that once they grow "large enough", they can eat/kill your fish. However, I have never been able to find a photo/proof on these forums of a bristle worm attacking/eating a fish while it is still alive. Of course they will eat inverts or fish that have died of natural/other causes. But they have not been proven to be a true predator.

Fire bristle worms on the other hand are a different story, supposedly.

I’ve heard bristleworms have been known to attack clams from the bottom but I’ve never had a clam so no firsthand knowledge there

 

[DeniseAndy]

I have had clams for over 15 years and never noticed an issue with bristleworms. They have all been sand placed eventually also. So, FME not to worry.
Now, bristelworms are scavengers, so if the clam was failing or dying maybe a person saw one near. Even in my old age clam that deteriorated over weeks, no bristle worms. This is in my 210g that has plenty in there.