Friend or Foe?!?!

[mattnbecs]

I know the generally bristle worms are good for the aquarium, but this behemoth has me a little worried. I have seen about 3.5 inches of him sticking out from under the rock, in complete daylight (so he is not shy). I am guessing there is quite a bit more in there too.

He seems to be picking up little bits of rock and moving them in front of his entrance, as you can see in the second pic.

I he is an interesting critter, but can anyone confirm whether he is a friend or foe? Should I get him out?

PIC#1
http://s299.photobucket.com/albums/mm283/mattnbecs/?action=view&current=DSCN7865.jpg

PIC#2
http://s299.photobucket.com/albums/mm283/mattnbecs/?action=view&current=DSCN7868.jpg

Thanks
Matteo

[Tylt33]

It looks like your typical bristle worm, which is considered "good" because it is a detrivore. However, I had a huge one (.5" thick, 1' long) that made me queasy to look at, and my pair of firefish shared a hole with it and would frequently be covered in bristles (hundreds, covering the eyes as well), which I don't think was "good" for their health.

He shouldn't eat your living animals or corals though, if that's what you're worried about.

[mattnbecs]

Yes, I would like to avoid any harm to the other tank inhabitants.

I amazed your firefish didn't relocate after getting stung multiple times. I know I would have :-)

[Tylt33]

<a href=showthread.php?s=&postid=14283926#post14283926 target=_blank>Originally posted</a> by mattnbecs
Yes, I would like to avoid any harm to the other tank inhabitants.

I amazed your firefish didn't relocate after getting stung multiple times. I know I would have :-)

They pick their "bolt holes" and seem to stick to them. I felt awful for them. They looked like pincushions.

[Tylt33]

Coincidentally, I gave away a bunch of rock from my tank, one of which contained the aforementioned bristle behemoth. The reef club member I gave the rock to came across it unexpectedly one day and said he almost screamed. Those things are horrible looking, especially when huge.

[blacklabel]

ive seen ones that were like 3 feet long. i would freak the **** out if i saw one of those in my tank

[dwd5813]

wow, that's a cool looking one. the one bristleworm i've seen in my tank is the type with a red end and mostly darker body.

[shuguley]

That doesn't look like any bristle worm I've ever seen, looks more like a leg of a brittle star to me, here's a pic off of Melev's ID site of a green brittle star.

Melev's Worm and star Id page (http://www.melevsreef.com/id/crawls.html)

http://www.melevsreef.com/id/inverts/green_brittle.jpg

[dwd5813]

actually that kinda looks like a eunicid worm. if that's what it is you'll want to get it out of there but i'd look for a more positive i.d. first.

[Whys]

It's a bristle worm. I have one just a little smaller then that, same coloration.

I've heard differing opinions once they get that big. Some say they'll dine on corals, others have said they only dine on dying corals and get a bad reputation for doing something good. I'm inclined to believe the second of these two statements.

They make traps if it makes you uneasy.

[Whys]

Or just give him a friendly name, like... Cuddles or Itchy. :]

[singold]

Personally, I'd remove it at this size. BTW for shuguley's post, green brittlestars have a reputation for being fish killers.

[Tylt33]

Everyone that has owned a bristleworm of that color knows what it is :) And brittle stars legs don't retract like a telescope.

[Crustman]

That is definately a polychaete and likely a nereid or nepthyid bristleworm. I had one like that lasso the foot of my anemone.

[orgtizz]

Question: In the second pic (original post) there is a small snail on the right side. Does anyone know what type of snail it is, and is it harmless?

[pagojoe]

The snail will be harmless. The worst it can be is one of the grazers that also includes sponges in its diet, but those eat the sponges that grow on the undersides of rocks that you don't normally see. You'd have to take it out and photograph it in a dish of water from several angles for me to have a good chance at an accurate ID. Someone else will probably suggest it's either a Collonista or a Sundial. I'm 99.9% sure it's neither.

Cheers,



Don

[mattnbecs]

I literally have hundreds of those snails. They seem to be harmless. They come out at night, and if there is a little algae on the glass, I have counted 60+ in one sitting, as they graze on it.

[longdangler]

I have one that looks just like that in my tank, probably 8-10". Redish to white during the day, almost blue at night, but I have moonlights on. He is fine now that I have fish and started feeding them. Before that I had just LR and a Crocea Clam, also CUC. Watch him take a few of my snails out during the day, Also after a month or so took out my clam from the bottom up.

Like I said been fine for a several weeks now, but I have extra food with fish. My general rule of thumb is that they are good when they are small but when they get to that size, if you aren't overfeeding then they are going to take something out because they get hungry too.

[Whys]

<a href=showthread.php?s=&postid=14288003#post14288003 target=_blank>Originally posted</a> by mattnbecs
I have counted 60+ in one sitting

That must have been a slow night here on RC. :D

[mattnbecs]

ahah.... not really. Just sat there with a beer, enjoying the tank. Nothing much was going on in the tank, so I just started counting