For me, if we are talking about just Kisame alone, he is a good combo of immobilizing the enemy while killing them softly. ;P He can absorb all chakra of your opponent while slowly killing them with your standard attacks at round 3-5 because of the taijutsu damage boost at 40+ chakra. So I think, if you include him with your Fire main, it would still be a decent combo because of the immobilizing skills your main has. But for me, Kisame works good with Water, Earth and Wind main.