thanx sushigirl. been hard tryin to id them with google images. some report a single or a pair of arms. in my case there are many. most say they are rather harmless. im just curious. my tank is stocked with fish, rocks, sand, mullosks, corals, clams and plants n organisms that i collected while at work (clamming). the only thing not is the water (that i mixed from the store salt) but have been slowly replacing it with local seawater that i collect from behind the hatchery which always reads 7.8 pH 0ppm NH3/NH4, 0ppm NO2, and 0ppm NO3. the salinity tends to range between 36 and 30ppm. its begun to grow naturally quite nice now but the only thing im concerned about so far are those worms. iv rejected certain specimens already for fear of the unknown so id rather not have to start over. if u know of any good lynks or info please share.