Is this a bristleworm?

[Arkayne]

Found him towards the end of my light cycle climbing the back wall. He was heading through the overflow towards the back of the AIO sump section.

It's very pale, almost completely white and easily 6 inches long stretched out.

Is it safe for my tank? I have a full reef tank, inverts, coral and fish including a yellow clown goby.

Any help is appreciated.

 

[ISpeakForTheSeas]

Welcome to Reef2Reef!

I'm thinking it may be a Eurythoe sp. fireworm such as Eurythoe complanata; if so, it's not reef-safe, as it may eat sedentary inverts (including corals, though they should prefer other foods over corals):

Yeah, to my knowledge pretty much anything that might be called a fireworm (genera Hermodice and Eurythoe) are coral or other sedentary invertebrate eaters - that said, the way they eat is pretty abnormal:

"Fireworms are voracious predators that feed on soft and hard corals, anemones, and small crustaceans. They engulf the last few centimeters of the tip of a branching coral, such as Acropora cervicornis (staghorn coral), in its inflated pharynx and remove the coral tissue right from the skeleton. They typically spend 5-10 minutes at each branch tip, visiting several, and the “skinned” branches are apparent by their white ends."
Source:

https://www.marinebio.org/species/bearded-fireworms/hermodice-carunculata/

That said, fireworms are opportunistic scavengers that eat pretty much anything they can get, though at least some of them seem to have a strong preference for fish - importantly, they also lack teeth, so they won't be preying actively on any fish in your tank; they have to be able to fit the entire piece they're eating in their mouth.

Tough, armed and omnivorous: Hermodice carunculata (Annelida: Amphinomidae) is prepared for ecological challenges | Journal of the Marine Biological Association of the United Kingdom | Cambridge Core

Tough, armed and omnivorous: Hermodice carunculata (Annelida: Amphinomidae) is prepared for ecological challenges - Volume 97 Issue 5

www.cambridge.org

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[Gtinnel]

Welcome to Reef2Reef!

I'm thinking it may be a Eurythoe sp. fireworm such as Eurythoe complanata; if so, it's not reef-safe, as it may eat sedentary inverts (including corals, though they should prefer other foods over corals):

I agree with the ID since I don’t see a caruncle to ID as bearded fireworm. However, it has always been my understanding that Eurythoe complanata are detritivores and scavengers and are generally reef safe.

 

[ISpeakForTheSeas]

I agree with the ID since I don’t see a caruncle to ID as bearded fireworm. However, it has always been my understanding that Eurythoe complanata are detritivores and scavengers and are generally reef safe.

Yeah, as mentioned, they prefer other foods first, so they shouldn't cause problems unless they're underfed or their population gets out of hand.

 

[Arkayne]

Thank you both for the quick and detailed response!

I haven't seen any more worms in my tank like this one. A few bristleworms here and there but much much smaller. I'm sure there's probably more but I don't think the population would be out of hand.