Fire main needs high cost paid event ninjas to be effective in arena you would lose all the time with your current ninjas in arena they don't go well with fire main. Most of the good fire ninjas are really hard to get and the cheapest fire ninja costs around 3-9k ingots Hanzo. I would suggest you use a rooted light main team with anbu itachi sasuke and mifune.

try Danzo with anbu itachi and fire main though I doubt it will be effective. Fire teams generally have 2 or more rares.