How big are your clowns? 3 of them will probably be trouble. Get rid of one of them and eventually you'll have a breeding pair. I had a firefish with my 2 clowns in a 20gal with no problems. The firefish was very shy and died due to stress after some tank maintenance. 
		
	
		
		
		
		
		
	
		
		
	
	
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