Fireworm?

[SHildebrand]

It’s the middle of the day and I just fed some phyto feast live. This thing came flying out after a minute. And is still hanging around.

 

[fishface NJ]

Looks like a bristleworm

 

[Privateye]

It's likely just a common species of bristleworm, which are polychaetes just like fireworms. The venom of a fireworm is extremely painful though, and the venom of a bristleworm is annoying at its worst. I probably get stung a few times a month. It's less-itchy than a mosquito bite, and the worst ones I've had were far less painful than a bee sting.

Not fun to grab with your bare hand, but it's nothing harmful. These used to be considered bad guys, but now some people consider them part of their cleanup crew. To each their own.

Arrow crabs will eat them.

 

[SHildebrand]

It's likely just a common species of bristleworm, which are polychaetes just like fireworms. The venom of a fireworm is extremely painful though, and the venom of a bristleworm is annoying at its worst. I probably get stung a few times a month. It's less-itchy than a mosquito bite, and the worst ones I've had were far less painful than a bee sting.

Not fun to grab with your bare hand, but it's nothing harmful. These used to be considered bad guys, but now some people consider them part of their cleanup crew. To each their own.

Arrow crabs will eat them.

I never had one before, and it just kind of freaked me out. It came out like an octopus arm out of nowhere and this guy‘s been quite active for 20 minutes now. But a trochus snail and a peppermint shrimp went by it and it hid so not sure how predatory it is.

 

[SHildebrand]

 

[Privateye]

They definitely aren't winning any beauty contests. It's really satisfying to pull out a big one with some forceps, and unless you want to see more in your tank you may want to try to remove it now. Or you can leave it if you like it!

 

[SHildebrand]

They definitely aren't winning any beauty contests. It's really satisfying to pull out a big one with some forceps, and unless you want to see more in your tank you may want to try to remove it now. Or you can leave it if you like it!

So I picked up a frag on the other side of the tank today and a smaller bristle worm was underneath it a fraction of the size of the one in the picture. Then I noticed underneath the cave area where the larger bristle worm pictured resides is one of my trochus snail shells upside down picked clean.

 

[BryanM]

If the bristles look like small paint brushes (IMO this one does), it is almost certainly a fireworm, and therefore will sting you, which apparently is most unpleasant.

 

[Privateye]

So I picked up a frag on the other side of the tank today and a smaller bristle worm was underneath it a fraction of the size of the one in the picture. Then I noticed underneath the cave area where the larger bristle worm pictured resides is one of my trochus snail shells upside down picked clean.

Sounds like they're already reproducing then, which can be tough to avoid. Their larvae are planktonic so all it takes is a little water to transfer them to your tank, let alone individuals or eggs.

They will go after any dead animal. I haven't heard about them attacking live snails, but there are many reports of them going after small fish. I've never seen that, and I know in some cases the fish likely died first and they just found worms eating it, but there have been enough stories that I still don't really trust them.

My clown goby and circus goby have been fine alongside bristleworms for years. They're the smallest marine fish I keep.