for the most part bristle worms are beneficial scavengers.....chances are you have way more than just the one you are seeing......if you are dead set on getting it out, you could try a bottle trap......or just take the violent route

.....just dont touch it with your bare hands, use tweezers or gloves to handle them
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260g mixed reef, 105g sump, water blaster 7000 return, Bubble King SM 300 skimmer, Aqua Controller Jr, 4 radions, 3 Tunze 6055s,1 tunze 6065, 2 Vortech MP40s, Vortech MP20, Tunze ATO, GHL SA2 doser, 2 TLF reactors (1 carbon, 1 rowa).
http://www.canreef.com/vbulletin/showthread.php?t=50034 . Tank Video here
http://www.vimeo.com/2304609 and here
http://www.vimeo.com/16591694