Hitch hiker question - Can anybody identify these please?

[ed84g]

Hi, im new here (after posting a couple of times on another forum). Ive browsed the forum for a while and read a lot of helpful posts as well as loving the giant build threads!

Anyway... Ive recently set up my first saltwater aquarium and added live rock about 3 weeks ago. My tank holds 135 litres of water excluding the rock.

There were a couple of hitchikers in the rock including some starfish however one of the rocks had a number of these worms in it (photos below) and over the last couple of days they have expanded across the other rocks and now there are about 20 of them at a guess. Are they something i should be concerned about and/or remove? I have tried searching online for them and had no success in finding out what they are so any help would be greatly appreciated!

Also, a couple of the rocks have the spongy looking things that you can see in the last photo on them... Does anybody know what this is?

Thanks

[Kitsune_Gem]

The worms are a good CUC. : D Theres also a feather duster in there, and what looks like a sponge of some sort. All good.

[Reefmedic79]

+1 the worms are bristleworms, the sponge is just that, a sponge. None of the critters pictured are anything you need to worry about, IMO.

[ed84g]

Thanks for the ID.

I guess ill leave them for now and only get rid of them if they get out of hand. Im planning on getting coral down the track and ive read that bristle worms can be an issue for coral so maybe ill leave them until that point.

Do they multiply quickly or is it easy to sustain their population?

[genesisblue]

Bristle worms are good for your tank. I've never had any problems with bristle worms and my corals. The worms are good detritus cleaners. Just make sure not to touch them, they are spiny and they cause me swelling.

[EricSIny]

Bristle worms generally only become a problem when they get very big (15-20+ inches)

I'd say you got a nice little clean up crew out of that rock.

For the future here's some good links to help up ID more critters you may find
http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml
http://www.chucksaddiction.com/hitchhikers.html
http://www.melevsreef.com/id/

[ed84g]

Thanks for the links... Interesting reading!

There are a LOT of sponges on the rocks which is good!

Ive also found a brittle starfish (identified thanks to the article!) along with a lot of slugs and last night this little fella popped out for the first time. At first i though "**** that looks scary" but apparently urchins are good for cleaning that tank so ill leave it in there and avoid getting near it with my fingers!!!

[exodus]

That's a very cool little hitch hiker there. Urchins are more rare to come by... You may want to find out how big it gets, though.

[ed84g]

hahaha you are making me nervous with the "may want to find out how big it gets" bit!!!

[T-dub]

Where did you get your rock from?

[ed84g]

From a local fish shop in Adelaide called Aggies Aquariums http://www.aggiesaquariums.com.au/ . They had premium live rock there that they wouldn't sell me so this is the regular stuff. It was pretty cheap as well!

There are loads of feather dusters in it as well including 2 awesome looks red and white ones and a stack of slugs which can only be a good thing!

[exodus]

I say that because some species of urchins can get quite large. With the 135 litre tank, the tank may be too small. You likely have some time to figure it out though since they don't grow super fast.