If the akatsuki ever fought each other without using ninjutsu or genjutsu or without any weapon, surely kisame will come out on top.
1: Kisame
2: Itachi
3: Obito
4: Hidan/Kakuzu
5: Sasori/Deidara/Orochimaru
6: Kabuto
7: Zetsu
8: Konan/Nagato
I have calculate using a persone strength and speed...