Could be a chiton, a super-limpet, no knowing unless I catch it in the act, (sometimes a flashlight can surprise midnight raiders in a tank) ---but it is cleaning rocks down to white limestone where it's been, and I've had nothing capable of that show itself in years. Still, there's plenty of rockwork back there it could have been noshing on. 
It's a gift, whatever it is. Urchins can do that sort of thing, but I haven't had rocks cast asunder as urchins will.
Tis a puzzlement.
				
			It's a gift, whatever it is. Urchins can do that sort of thing, but I haven't had rocks cast asunder as urchins will.
Tis a puzzlement.
 
	 
 
		 
 
		 Haven't had anything that long but I did move a system once where we found a ~4" Majestic Angle the owner hadn't seen in over 3 years.  He had bought it as a juvinile and also had roughly 2 lbs of live rock per gallon.   I suspect he never really sat and wathced his tank but the Majestic had tons of space to swim around without being seen.
   Haven't had anything that long but I did move a system once where we found a ~4" Majestic Angle the owner hadn't seen in over 3 years.  He had bought it as a juvinile and also had roughly 2 lbs of live rock per gallon.   I suspect he never really sat and wathced his tank but the Majestic had tons of space to swim around without being seen. 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		