Large worm appeared at night

[Marco333]

I was just checking on my tank after the lights went out and a large worm was sticking out of the hole that my shrimp and goby live in. Should I be worried about it? I only saw the part sticking out and it looks huge.

 

[ScottandAlisa]

Bristle worm. I usually wouldn’t worry because they’re a somewhat beneficial clean up crew some may say, but I dont know if it would effect your goby/shrimp pair. Hopefully someone else knows better than I do!

 

[JumboShrimp]

They can indeed get large (and numerous). I saw one on an online video once from a guy who had his tank up and running for a long time, and when he finally broke it down he found a bristle worm in there he never knew was lurking in the tank—and it was about 2 feet long! Read up on them; some people love them / find them beneficial, other people hate them and manually remove them or acquire fish that will eat them. You’ll have to decide for yourself which way you want to go. Just make sure it is not a fireworm!! — research the difference, as they look quite similar. (From that one photo, yours does look like a bristle worm.) And by the way, they rarely are seen except at night, so you may in fact have more that that one in your tank. Hope this helps

 

[Luna]

What fish eat them?

 

[JumboShrimp]

Do a “search” here on Reef2Reef and you will surely find some tips— but a Melanurus Wrasse, for one. It’s a super-cool fish that will be in constant motion among your rock work... other than when it is buried under the sand at night (or wedged in a rock) to sleep.

 

[sfin52]

Wrasse and coral banded shrimp but those also can go after feather duster and shrimp.

 

[Marco333]

Thanks for all the replies. Looks like it’s a bristle worm which I shouldn’t be worried about.

 

[cristata.reef]

They can indeed get large (and numerous). I saw one on an online video once from a guy who had his tank up and running for a long time, and when he finally broke it down he found a bristle worm in there he never knew was lurking in the tank—and it was about 2 feet long! Read up on them; some people love them / find them beneficial, other people hate them and manually remove them or acquire fish that will eat them. You’ll have to decide for yourself which way you want to go. Just make sure it is not a fireworm!! — research the difference, as they look quite similar. (From that one photo, yours does look like a bristle worm.) And by the way, they rarely are seen except at night, so you may in fact have more that that one in your tank. Hope this helps

That's a eunicid, not a bristle. True bristles are detritivores. And yes fireworms are quite nasty in addition to being predatory of small inverts like amphipods and other polychaetes (but not opposed to the occasional sleeping fish).

OP you have a large bristle worm and on occasion they do share burrows with gobies/shrimp (which has also been documented in the wild)

 

[MTBake]

I've seen several large bristle worms in my tank recently. I've seen one stretch out as far as 8 inches and still didn't see the tail end. I've seen them near my goby/shrimp burrow. But never coming out of it like that.

 

[E_reefer]

Great picture! Indeed, strange creatures lurk in the darkness.