I've just made a fascinating discovery in my live rock - a bristleworm has taken up residence, despite the issues that led to the loss of my fish, my snails, hermits, and two of my corals are still doing remarkably well.
This morning, I came across a rather lengthy bristleworm, predominantly grey with white, setae-like appendages - I know they're not actually legs, but for now, that's what they'll be referred to. Researching information on this particular species has been a bit of a challenge, with numerous conflicting opinions and recommendations across various sites.
I was hoping to tap into the expertise of the knowledgeable members here, whose opinions I hold in high regard - could you please enlighten me on the following:
a) Is this bristleworm one of the more benign or problematic varieties?
b) What's the best course of action to take regarding its presence in my tank?
c) Are there any other essential factors I should be aware of?
(My wife was less than thrilled about the discovery, jokingly accusing me of harbouring millipedes in the tank.)
About bristleworms
Re: About bristleworms
I'm no expert, but I've always thought worms didn't exactly have legs, right. Bristleworms, in particular, are known for their bristles, not legs.
Considering the vast number of bristleworm photos available online, would it be possible to find one that closely resembles the one you've found and share a link. This might help confirm the identity of your tank's inhabitant. It's possible that it could be something entirely different.
Considering the vast number of bristleworm photos available online, would it be possible to find one that closely resembles the one you've found and share a link. This might help confirm the identity of your tank's inhabitant. It's possible that it could be something entirely different.
Re: About bristleworms
Bristleworms are generally harmless in a tank like yours, they're just scavengers that feed on detritus and leftover food. I've got similar ones in my tank, they don't cause any issues and only come out at night to clean up. They're pretty much like little vacuum cleaners for the tank. The only one I'd be concerned about is the fire bristleworm, but that one's red, not grey like yours.
Re: About bristleworms
I've found a couple of images that look pretty similar to my guy -
http/www.teara.govt.nz/NR/rdonlyres/7D64...283/p6887pc.jpg
and this one
http/www.reefcorner.com/images/BristleWormLarge.jpg
http/www.teara.govt.nz/NR/rdonlyres/7D64...283/p6887pc.jpg
and this one
http/www.reefcorner.com/images/BristleWormLarge.jpg
Re: About bristleworms
Most likely just a scavenger, I'd say. The ones to worry about are Hermodice, they're bright red and active during the day, known to eat coflakes, and they originate in the Caribbean. On the other hand, it could be a eucinid - some of these are predators, so it's worth doing some research online to confirm.
Re: About bristleworms
I think fireworms are pretty unmistakable, being bright red or neon orange with white bristles - clear predators. Most worms you find in the tank are just harmless scavengers.zenoxa wrote: ↑Sun Jun 29, 2025 6:16 am Most likely just a scavenger, I'd say. The ones to worry about are Hermodice, they're bright red and active during the day, known to eat coflakes, and they originate in the Caribbean. On the other hand, it could be a eucinid - some of these are predators, so it's worth doing some research online to confirm.
Re: About bristleworms
Thanks for the info, I really appreciate it. My tank seems to be recovering well - the coflakes that survived are thriving better than ever. I'm planning to restock in about a week, which should coincide perfectly with the end of the cycle.
I'd love some help with stocking ideas, though. Every fish I research seems to require a 20-gallon tank or more, but my cube is only 12 gallons. I'm particularly keen on keeping a rainbow blenny, and I'd also like to introduce something to keep the critter population in check, given my live sand is teeming with life.
I was thinking of a 6-line wrasse - would that be a suitable choice? I know it might grow too big for my tank eventually, but I'm hoping it could be a useful critter controller in the short term. We're planning to upgrade to a larger tank when we can afford it, so I could always move the wrasse to the new tank if needed.
Oh, and congratulations to Ski on becoming a mod - well deserved.
I'd love some help with stocking ideas, though. Every fish I research seems to require a 20-gallon tank or more, but my cube is only 12 gallons. I'm particularly keen on keeping a rainbow blenny, and I'd also like to introduce something to keep the critter population in check, given my live sand is teeming with life.
I was thinking of a 6-line wrasse - would that be a suitable choice? I know it might grow too big for my tank eventually, but I'm hoping it could be a useful critter controller in the short term. We're planning to upgrade to a larger tank when we can afford it, so I could always move the wrasse to the new tank if needed.
Oh, and congratulations to Ski on becoming a mod - well deserved.
Re: About bristleworms
I'm no expert, but I've always thought worms don't have legs. Bristleworms, in particular, are known for their bristles. I can see why you'd call them legs, though - I've been there too, struggling to recall the right term. Setae, I think, is the word you're looking for.