please help me identify these!

[jokelly61]

hello all, i have just got a new marine tank which has been established for a year and have seen this in my tank could anyone shed any light on to what it may be thank you seems to only come out when the night light is on as soon as I switch it to daylight it disappears back into the rock!

 

[geridoc]

These are bristle worms. Some hobbyists dislike them because they think they eat their fish, but actually they are an important part of your clean-up crew and one of the reasons you buy live rock is to get organisms like these. If you have too many of them, or if they are too big there are traps that can remove them, or you could just correct the water conditions that favor them (too much uneaten food is the usual cause, so just restrict your feedings).

 

[jay0705]

I agree. I have them in my tank and have no issues w them. I have fish,shrimp,snails and no issues

 

[jstdv8]

they are also one of the many reasons you should wear gloves when messing with rocks and corals in your tank.
Ive been stung a couple times and it itches like crazy. Vinegar ended up doing the trick though