How long do bristle worms get?

[DmitryB]

Just spotted this guy. Pretty sure that's a bristle worm and why is he so huge?

 

[fishface NJ]

I have had ones that were 18"ish

 

[Gumbies R Us]

One website I saw said they can get up to 24 inches long.

 

[EricR]

I have had ones that were 18"ish

Yikes! I've seen posts here showing gigantic ones like that which people find in plumbing and such.

I've had bristleworm populations in my tank(s) for the 5+ years since I started with live rock but have never seen a really big one.
Whether or not that means that whatever different species I happen to have just don't get that big, I have no idea but it is a curiosity that I have.

 

[DmitryB]

18'' is a snake, not a worm! So is it harmless at that size? Do I need to start extermination procedures?

 

[FrugalReeferJon]

 

[BryanM]

This would be rehomed immediately.

That thing is massive.

 

[keagan]

They can get really large even harmless species. I'm a big guy (big hands) and this is my hand next to a particularly large bristle worm.

 

[exnisstech]

This is one I transfered over when I moves tanks. I cleaned all the mulm and worms out of the old sump and dumped it all in the new one when I moved.
What's not to love.

Even the bristles in my finger don't hurt lol

PS. Im not sure how long they get I've seen some at least 6-8" crawling through the rocks but I don't see mine often unless i move something.

 

[allof fish]

18'' is a snake, not a worm! So is it harmless at that size? Do I need to start extermination procedures?

No chance that thing is 18in. Looks like it’s 36. They’re technically good for reef tanks and each all the detritus and stir the sand up but can bite and attack fish. Dont get bit it will hurt. But at that size that thing needs to go

 

[keagan]

No chance that thing is 18in. Looks like it’s 36. They’re technically good for reef tanks and each all the detritus and stir the sand up but can bite and attack fish. Dont get bit it will hurt. But at that size that thing needs to go

Some species of polychaete bite and attack fish there's over 10k species described most aren't predatory. The huge one in that video is a Eunice worm it'll eat fish

Edit:added of polychaete to clarify what I'm referring to.