Weird worm? What the bleep is this?

AGWL · May 14, 2023

Hi all! This little whatever started poking out of an empty shell (what background pics). Maybe about an inch or 1-1/2" long. I pulled the shell out and there may be a couple of other small ones in there, too (pink background pic). There's more on/in some rock work - pulled one off; missed another one. It doesn't look like a bristle worm to me. What is it and do I need to panic?

Stephen8169301 · May 14, 2023

I’m not sure what it is but maybe some will hopefully help you out following along

vetteguy53081 · May 14, 2023

AGWL said:
Hi all! This little whatever started poking out of an empty shell (what background pics). Maybe about an inch or 1-1/2" long. I pulled the shell out and there may be a couple of other small ones in there, too (pink background pic). There's more on/in some rock work - pulled one off; missed another one. It doesn't look like a bristle worm to me. What is it and do I need to panic?

very hard to i.d. on a paper towel but looks like a juvenile peanut worm - Not positive

jabberwock · May 14, 2023

I don't know, but I have learned to never panic about my tanks, unless water is hitting the floor. Then, you should panic...

I recommend the modified stationary panic as opposed to the full bore linear panic.

AGWL · May 16, 2023

Now with better pictures! What is this?

Snoopdog · May 16, 2023

Peanut worm, pretty sure. (good guy)

jabberwock · May 17, 2023

Did you see it swimming around, or was it staying in one spot?

AGWL · May 17, 2023

jabberwock said:
Did you see it swimming around, or was it staying in one spot?

That one came out of an empty shell that was one the substrate. I've also seen one on the glass and one (maybe the same one) on a rock, very obviously eating something. It disappeared when I tried to grab it. They (it?) seems to be maybe an inch long or slightly more and very thin. They curl up in a coil if you mess with them.

jabberwock · May 17, 2023

I had something similar, but it was swimming around in circles very quickly. A member on here said it was a type of predatory Dorvilleidae worm.

OrionN · May 31, 2023

It is a dead worm for sure. I would leave them be. Great majority of these worms are beneficial to the tank. Only once in a very long while there is a bad one. These animals are what cause "live sand" and "live rock" are great and essential in keeping a good, stable reef aquarium. I have worms that are 18+ inches in my tank.

AGWL · May 31, 2023

Yeah, whatever these are, I'm not stressing about it. They aren't as icky to me as bristle worms, for some reason. Was really just curious what they are and if I needed to worry. I've got detritus worms in my freshwater tanks, so no big deal as long as they're not harmful.

Alexraptor · May 31, 2023

AGWL said:
That one came out of an empty shell that was one the substrate. I've also seen one on the glass and one (maybe the same one) on a rock, very obviously eating something. It disappeared when I tried to grab it. They (it?) seems to be maybe an inch long or slightly more and very thin. They curl up in a coil if you mess with them.

Lightning fast? Covered in goo when you fish them out?

Did it look like this in water?