Worms!
 

I just got my new tank set up. I was watching the tank one night and I saw a shirmp of some kind. So im using a bottle trap with some shrimp in it to try and catch it. While obseriving it i notice TONS of worms trying to get at my bait. They are as long as 30 sm streched out. They are brown and kinda flat with many spines along the sides. They live in the live rock and only come out at night. what are they and are they harmful to my tank?

30 sm is that long

Do thee worm things look a lot like centipedes? They're most likely bristleworms. They are, for th most part, harmless and just eat detritus that falls to teh bottom of the tank. If your set up is a reef however, you might want to consider taking out the big ones (like your foot long bad boys... these guys can get much bigger if you let em)

Oh btw, don't touch em barehanded if at all possible. They can sting you.

anything over an inch is bad.they eat shrooms

I have mushrooms and I have lots of bristleworms larger than an inch (and other types of worms as well) and I haven't seen a 'shroom disappear as yet.

Actually, the bristle worms haven't been detrimental at all in the aquarium, just the opposite - detritus and decaying material eaters.

I have all kinds of worms in my tanks and they are good thing to have, they clean up a lot of Cr*p from your tank.
People dont like them because they look ugly but, worms may think the same about humans, we never know?
The only bad one is medusa worm http://www.seahorse-nw.com/Predators/IMAG031.JPG
(do google picture search if this link didn't work)
If this one dies all your fish will go to the fish heaven , same as black cucumber.

medusa worm? never heard of it. is it toxic?

It is when its dead.

ya most are beneficial but be cautious.check out oregon reef.comhttp://www.oregonreef.com/sub_worm.htm

Ok, but that's a prize-winning worm he has there :lol: