I just set up a saltwater aquarium the other day and I have been adding live rock for the past 2 days and I noticed that there were little yellow-ish spirals in the bottom of my tank... I stirred the water a little to remove them and when I looked at them closer they looked like little centipedes! They are maybe a centimeter long and look like tiny centipedes. The only place I can think I could get them or where they came from was that they may have hitch hiked on my live rock... they all died because the aquarium isnt cycled yet and I collected about 30 of the little things. Are they harmful to my tank? How big do they get? Any and all info is greatly appreciated!