‘I am putting some dead fish in the fox cubby – just cause”Strange, but just a figure of speech? Probably. The 'dead fish' term is one associated with Rahm Emanuel (he once sent a pollster a stinking dead fish to express his displeasure or something). The flak's reference might have been mocking in response to Sean Hannity's penchant for calling Emanuel "Rahm Rombo dead fish" on the air, which would make sense.
That is, unless it had some weird relation to the Bush-appointed staffer at Department of Homeland Security who was sent a package of dead fish and white powder before being terminated of her position as a WMD expert (was that ever explained?).
The emails are not a surprise, though. Every administration has favorites and enemies and every one tries to gain an advantage with the media. This one has the benefit of a very docile pool full of admirers who are afraid to upset the power and hence, don't often make waves or much news.