Lupin;3923719; said:Saying bad water conditions cause the presence of ich is rather misleading. Bad water conditions DO cause stress which in turn causes the ich to appear as outbreaks immediately. HOWEVER, ich can only be introduced if one of the fish is already carrying it. Unquarantined specimens make a nice entry point for ich towards your other stocks. That is why you SHOULD quarantine every new fish for 3-4 weeks, no less than that.