Is my urchin hosting a bristleworm?

[Naja]

Hey guys!

I have a Blue Tuxedo Urchin (Sonic is his name), that I've had since middle of november. I dont exactly recall when I first discovered this worm he is carrying around, but it's been with him for a little while. It's been difficult to get a good look at it, since he seems to be hiding underneath the Urchin or among his spines during the day and I can only see it at night, sometimes. This worm thing also dont like it when I shine a light on it and hides among Sonic's spines when I try to look at it with the flashlight.

When I first discovered the worm I freaked out, thinking it was something bad that was hurting Sonic, but as I looked it didnt seem to bother him, and there was no damage to Sonic anywhere. The worm is still living with Sonic, but Sonic does not seem to be bothered at all. There is no damage on him as I can see, the worm only walks/crawls on him, around his spines and doesnt seem to be hurting him at all. Sonic has not dropped a single spine as I can see, he is eating algae off the glass, rocks and sand like a machine, and is growing. As I have been observing this it seems like it is some sort of a symbiotic relationship going on, as if Sonic provides safety with his spines, and this worm is keeping Sonic clean and gets food from Sonic when he does his thing. Is this even possible? I have been meaning to take photos and ask here, but Sonic has not been willing to pose easy for me. I've also considered trying to remove this worm, but as I dont always see it, and removing it would be difficult and probably very stressful for Sonic, I have just observed and decided that if I see anything harmful happening, I would remove it. I did manage to get a couple of photos now though, and I am really curious to what it is.

Is this a harmless bristleworm of some sort that is safe to keep, or is it something potentially bad I should try and remove?

Thanks

 

[sfin52]

Great looking photo. I have no idea what the worm is. @KJ

 

[KJ]

I'm at work now on my cell phone hard to tell from the picture.

 

[KJ]

I have been doing some research on urchins and worms and haven`t come up with anything, it looks a little bit strange and cool at the same time.I am not for certain what kind of worm this is , it is hard to tell from pic,if it is a bristle worm , as long as it doesn`t do any harm to the urchin, I would let him be, every day it is cool to see these strange relationships that we haven`t seen before. It is hard to be spot on about some things that we see.Mother Nature likes to throw curve balls every day! Does this worm look like this?

 

[Naja]

I have been doing some research on urchins and worms and haven`t come up with anything, it looks a little bit strange and cool at the same time.I am not for certain what kind of worm this is , it is hard to tell from pic,if it is a bristle worm or different species of worms, as long as it doesn`t do any harm to the urchin, I would let him be, every day it is cool to see these strange relationships that we haven`t seen before. It is hard to be spot on about some things that we see.Mother Nature likes to throw curve balls every day! Does this worm look like this?

Thanks for your reply!
It's hard to describe how it looks, it doesnt look quite like your picture, it doesnt seem to have such long legs, and the legs seem to be much closer together on it. It also tapers in at the back, almost to a point. It's fairly pale, with what looks like a white stripe over its head. It's difficult to tell how long its legs are, as they either are very close together making it hard to tell them apart, or they are very short. They are many though. The worm is quite flat, and seems to have two "tongues" or "tentacles" that it seems to be using to either scavenge with or feel his surroundings with (you can barely see them in the zoomed in pictures). It's also hard to get a really good look at it, as it tends to slide off into the urchin's spines as soon as I try to shine a light on it. It's interesting to watch though, I cant see the worm when the lights are on, but when the lights are off, I can see it crawling among his spines like it's cleaning them or something.

I'll post the direct links to the pictures, as they are quite big and can be zoomed quite a lot, if it helps any.
https://i.imgur.com/3DKF0Y7.jpg
https://i.imgur.com/1TQYShe.jpg

 

[KJ]

It's really hard to tell from the picture what can worm it's is.

 

[KJ]

Thanks for your reply!
It's hard to describe how it looks, it doesnt look quite like your picture, it doesnt seem to have such long legs, and the legs seem to be much closer together on it. It also tapers in at the back, almost to a point. It's fairly pale, with what looks like a white stripe over its head. It's difficult to tell how long its legs are, as they either are very close together making it hard to tell them apart, or they are very short. They are many though. The worm is quite flat, and seems to have two "tongues" or "tentacles" that it seems to be using to either scavenge with or feel his surroundings with (you can barely see them in the zoomed in pictures). It's also hard to get a really good look at it, as it tends to slide off into the urchin's spines as soon as I try to shine a light on it. It's interesting to watch though, I cant see the worm when the lights are on, but when the lights are off, I can see it crawling among his spines like it's cleaning them or something.

I'll post the direct links to the pictures, as they are quite big and can be zoomed quite a lot, if it helps any.
https://i.imgur.com/3DKF0Y7.jpg
https://i.imgur.com/1TQYShe.jpg

YW

 

[Naja]

It's really hard to tell from the picture what can worm it's is.

Absolutely understandable, I'll see if I can get better photos. Only problem is that requires Sonic to be on the front glass with the worm between him and the glass, and me being super quick with taking a sharp photo at night, from a distance without blitz flare, before the worm understands I'm taking his picture. Sonic tends to prefer the back glass, it's more algae there, haha!

 

[KJ]

This is a strange one.
@Lovemyreef2015 @Jose Mayo

 

[Lovemyreef2015]

I'm going to say it's a type of bristle worm. It could have been out Scavenging and accidentally got caught by the urchin. I couldn't find anything that would suggest that the bristle worm would hurt it but I would be cautious. If you can remove it with tweezers without hurting the urchin then that's what I would suggest doing.

 

[TinyChocobo]

KILL IT WITH FIRE!!!!

JK.

Very interesting indeed.

 

[Jose Mayo]

This is a strange one.
@Lovemyreef2015 @Jose Mayo

Does not look like a bristle worm to me. It looks like some kind of nudibranch epibiont or symbiont, or merely "captured" by urchin, maybe, but I could not find anything to confirm this.

Regards

 

[TinyChocobo]

You don’t see me! I’m not an urchin! I’m a worm.

 

[paphater]

Is the worm alive? The only time I've seen them white like that is when they are dead.

 

[Naja]

I'm going to say it's a type of bristle worm. It could have been out Scavenging and accidentally got caught by the urchin. I couldn't find anything that would suggest that the bristle worm would hurt it but I would be cautious. If you can remove it with tweezers without hurting the urchin then that's what I would suggest doing.

I dont know, it seems like it would easily be able to walk off the urchin if it wanted to. It moves over his spines, between them, and on his blue non-spiny parts without any trouble. Removing it would be difficult and probably very stressful for the urchin, as I don't think I can remove it without first taking the urchin out of the tank. I tried poke it before and it was quite fast. But the urchin does not seem bothered or hurt in any way.

Does not look like a bristle worm to me. It looks like some kind of nudibranch epibiont or symbiont, or merely "captured" by urchin, maybe, but I could not find anything to confirm this.

Regards

I have not considered this, as my knowledge of nudibranches is quite slim, I only know what to look for regarding zoa-eaters and monit-eaters and other coral munchers, and that's pretty much it as I'm very new to the hobby. What kind of nudibranches would look similar to this one? I was thinking flatworm at one point, but then there is the legs this one has.

Is the worm alive? The only time I've seen them white like that is when they are dead.

It is very much alive

 

[Jose Mayo]

I tried poke it before and it was quite fast.

What kind of nudibranches would look similar to this one?

If it's "quite fast", it's not a nudibranch. I was wrong.

Regards

 

[cristata.reef]

Sounds like a scale worm which are known to host sea stars. Since sea urchins and sea stars are both echinoderms I will assume that they can host them too. Hope that helps a bit!