Eunicid worm or bristle worm?

[amigo003]

I found this worm in my tank and it’s huge, I know I have bristle worms but this guy looks a little different, he’s all pink.

Is this a bristle work or a eunicid worm?

should I leave it or remove him?

 

[srobertb]

Hard to tell. Pics blurry. Video broken.

Google bristle worm. Google Eunicid worm. Note how bristle worms instead of legs appear to have brush-like bristles running along their sides. They can be segmented but will look like little tufts of bristles.

A Eunicid worm can share coloration and size as a juvenile but will have more pronounced appendages off its body (more like a stubby legged centipede).

Look at the head. A Eunicid has a more complicated and developed head with pinchers and things while a bristleworm does not.

Does it have a den with a door? They will make a den and place something in front of it to act as a door.

I fought (and I say fought because it was a legendary battle) a very large Eunicid Worm. First off, it was a ninja. It managed to grow to well over a foot and thicker than 2 pencils and stay hidden in a 29g bio cube for a year +. Bristleworms on the other hand, if they don’t fear your fish, will be out whenever food enters the tank.

They are aggressive. I am a huge fan of the “poke it with a stick” approach to life. If it attacks the stick, it’s a problem. If it balls up or hides, less of an issue.

Bristle works can get huge. I believe literally the sky is the limit on size. I’m a big fan of them and have seen some that are much bigger and thicker than your friend here.

 

[ISpeakForTheSeas]

Just for clarification here, bristle worm (while generally used in the hobby to mean a harmless polychaete worm) is actually a generic term for all polychaete worms (the bristles of the worm being called chaetae; polychaete basically = multiple chaetae). Oenone fulgida is a eunicid polychaete. The infamous bobbit worm is also a eunicid polychaete. However, not all eunicid polychaetes are predatory/bad.

Eunicid worms have tentacles on their face (typically five tentacles), so they’re usually pretty easy go identify (and, while a few Eunicids are predatory like the bobbit and Oenone fulgida, most are actually harmless/beneficial).

 

[amigo003]

Hard to tell. Pics blurry. Video broken.

Google bristle worm. Google Eunicid worm. Note how bristle worms instead of legs appear to have brush-like bristles running along their sides. They can be segmented but will look like little tufts of bristles.

A Eunicid worm can share coloration and size as a juvenile but will have more pronounced appendages off its body (more like a stubby legged centipede).

Look at the head. A Eunicid has a more complicated and developed head with pinchers and things while a bristleworm does not.

Does it have a den with a door? They will make a den and place something in front of it to act as a door.

I fought (and I say fought because it was a legendary battle) a very large Eunicid Worm. First off, it was a ninja. It managed to grow to well over a foot and thicker than 2 pencils and stay hidden in a 29g bio cube for a year +. Bristleworms on the other hand, if they don’t fear your fish, will be out whenever food enters the tank.

They are aggressive. I am a huge fan of the “poke it with a stick” approach to life. If it attacks the stick, it’s a problem. If it balls up or hides, less of an issue.

Bristle works can get huge. I believe literally the sky is the limit on size. I’m a big fan of them and have seen some that are much bigger and thicker than your friend here.

I ended up finally catching the guys. Had to remove a ton of turf algae (wish something would eat that stuff) off a rock it was under. I took more pictures. What would you call this thing? I placed a bristle worm next to it.

 

[amigo003]

When I touch him he shrinks and appears to run. Here’s picks of his head

 

[JoJosReef]

Not a eunice worm--a Eunicid would be terribly hard to catch in any case and would likely break up its own body to regrow heads rather tha be pulled out of its burrow.

I've seen smaller specimens of these but haven't gotten an ID on them yet.

 

[amigo003]

Not a eunice worm--a Eunicid would be terribly hard to catch in any case and would likely break up its own body to regrow heads rather tha be pulled out of its burrow.

I've seen smaller specimens of these but haven't gotten an ID on them yet.

Should I toss them back in the tank or get rid of him?

 

[JoJosReef]

Should I toss them back in the tank or get rid of him?

This is by far the best site I have found to ID worms. I'd still have a problem ID'ing yours though. Have a look and you can make an educated guess. Where is your truck and substrate from? Gulf rocks/sand? Live rock from LFS? That can help with your decision too. I've found most of my gulf rock worms, even the eunicids, are mostly harmless detritivores. But I've been lucky in not getting fireworms and only one polyclad flatworm.

 

[JoJosReef]

doh
And link: https://chucksaddiction.thefishestate.net/hitchworms.html