Anyone with an electric elemental affinity should be able to take him down, therefore Darui, Sasuke, and Kakashi are three people who would be bad matchups for him
use raiton...or blast him to bits.....just keep him from regeneration and hes done...poison him or hit him with "a armada or tiny swords"(rasen-shiriken)
Amaterasu him,all the water would evaporate.Tsukyomi might also be able to kill him.Seals can kill anyone,Eg.Death Reaper Seal,Sword of Totsuka.Im really not sure if electricity can kill him,it was shown to affect him by making it hard for him to liquify but im not sure if he would die from it.You can also drain all his chakra,Eg.Samehada or Nagato's Pain path.Steal his soul using Nagato's pain path or gedo mazdo.