There are a number of tank inhabitants that you are going to run into when starting your tank that will surprise you. This one may even cause you a little pain. Bristle worms are often referred to as a dreaded pest however they are actually a very beneficial scavenger and detritivore. If you haven’t yet head the word detritivore it means something that feeds on detritus which is dead organic matter such as fish waste and dead algae. There are a few harmful species that actually do feed on corals, however most encountered shouldn’t cause any concern. Usually if there are a lot of them in your tank it is due to over feeding. Simply cut back on your feeding (make sure the fish get it before it settles to the bottom) you will see a reduction in their numbers quite quickly.
If you need to remove them from the tank or run across one of the larger species, I have found tweezers to be the easiest method of removal. I have also siphoned them out before when I was unable to catch them with the tweezers. DON’T GRAB THEM WITH YOUR BARE HANDS! While they look like a soft caterpillar those spines are actually made of calcium. When you grab them they break off in your skin and take a few days before the discomfort goes away. I have heard you can dry the area off and then stick duct tape on the location to remove some of the spines(I haven’t yet tried this as I have been fortunate to not have grabbed on in a while.
So don’t panic if you see them unless they appear to be attacking one of your corals, and if you need to remove them do so in a manner that doesn’t require your bare hands. Also, be careful when moving live rock and I recommend doing so with gloves just to avoid reaching under the back edge of a rock where they are living.
I have often used Aqua Gloves, it also keeps soap and oil from your arms out of the tank. They are also great for handling carpet anemones.