The stock fan should work just fine, but I understand it is quite loud.
If you are looking to replace the stock fan, I would recommend a
Noctua NF-A14 PWM.
Full tilt it offers 42.6% higher air flow and should be significantly quieter.
I have a pair on my Corsair H110 and the acoustical improvement is quite noticeable over the stock fans (which are supposedly quieter already than the Kraken series offers).