When I get a frag/coral/sponge that I can't separate from the base or there are dead areas of the base that are exposed I always cut off as much as I can and I cover the rest with superglue right up to and on the edge of the live tissue.  This helps reduce the potential for unwanted hitchhikers.   
 
Hopefully they have not spread elsewhere 
		
	
		
		
		
		
		
	
		
		
	
	
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