"Great minds think alike" wow, I was pondering doing that too, but then I remembered that Sabu-chan was in the Blitzball Stadium wannabe too, so he would end up toasted by the raiton, so I went for a menacing ball variation to be a straight attack instead of being an area attack, just to save poor Sabu.
I thought about using raiton as well but I figured in a situation like that the more larger concern would be air instead of chakra. If bee drowns or sabu drowns then the fight is instantly over for the both of them and kisame knows that. At the same time I figured it would make sense to have the fight take another different turn with hachibi using a humanoid flesh transformation similar to naruto in 6 tails only this one would have 8 arms thus making him a difficult person to fight hand to hand. Besides bringing out a super large beast would just be overkill.