critters

Question
Last night I was looking at my tank. about 2 1/2 months old. I saw what looked like tiny white worm/catapiller like animals on my live rock what are they? and are they good or bad. they were very small. thanks, mike

Answer
Hi Mike. There are thousands of different species of worms that can hitch hike into your tank on your live rock. Out of these very few are harmful. The ones that are harmful are usually large and only harmful to specific species of coral or sponge. Most likely a form of bristleworm. These contrary to what some belive, are very beneficial in a saltwater tank. They feed on detritus and debris in your tank that you can not reach. They also keep a good oxygen supply to your gravel bed by burrowing through it and cleaning out any debris.