white larav on a peice of my LR

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i was looking at my tank with a flashlight and on one peice there are little white larva all on it. they stay anchored to the rock but move their body and appears to be eating of the live rock. they are about the size of a sewing needle hole. anybody have any clue what they are? <img src="graemlins//confused.gif" border="0" alt="[confused]" />

 

[lerch]

Does it look like a white tube, kinda like a worm with a hole on one end. If it looks like this and is hard then it is a kind of feather duster worm. I have some of these and you can see the little feather duster come out of the open end. If does not look like this the I don't know, sorry.