I use Zatarain's Crispy Southern.
I put it in a zip lock bag dry with the fish and shake it up and put it in the deep fryer.
I have tried egg wash and it doesn't seem to taste any different.
It is light, crispy and doesn't retain fryer oil.
I get mine at Amazon but have been told Meijer carries it.
If you want a little spice to it add hot pepper.