They're two completely different champions aside from their "assassin" champ type...
You can't compare them.
At the current moment Fizz isn't played as much though due to meta shifts and nerfs.
Kha on the other hand is much better in jungle with the carry jungle meta.
Kha better jungle, and the battle is pretty even in mid.
Kha has better farming abilities for jungling and had great burst for ganking as well as short cooldowns, and he can do a lot with very few items
Fizz is extremely strong when he finishes his lich bane and sorcerer's shoes. He is very slippery when he gets zhonyas but he probably isnt the best choice as a jungler as he doesnt have realiable cc like kha does with his w and passive, woth fizz you have to hope they dont flash when you drop from your e.
Fizz is definitely better at assassinating people damage wise. But Kha is an overall safer pick.
As for who wins, Fizz or Kha? Id say its a skill match up.
I think it's the other way around, pre 6 it's a skill matchup because Kha would only win trades if Fizz is isolated, and post 6 Kha's evolved ultimate negates 50% damage from Fizz's ultimate
You can't compare them.
At the current moment Fizz isn't played as much though due to meta shifts and nerfs.
Kha on the other hand is much better in jungle with the carry jungle meta.
I would say Fizz is a better mid, if I must, and Kha is the better jungle... even though Fizz jungle isn't a thing.
Kha has better farming abilities for jungling and had great burst for ganking as well as short cooldowns, and he can do a lot with very few items
Fizz is extremely strong when he finishes his lich bane and sorcerer's shoes. He is very slippery when he gets zhonyas but he probably isnt the best choice as a jungler as he doesnt have realiable cc like kha does with his w and passive, woth fizz you have to hope they dont flash when you drop from your e.
Fizz is definitely better at assassinating people damage wise. But Kha is an overall safer pick.
As for who wins, Fizz or Kha? Id say its a skill match up.