Whether your dragon be Fire, Earth, Ice or Water their attacks are all the same. They all breath fire. So if your dragon is an Ice dragon it does not mean it will breath Ice. It only means that it's surrounds are of that what resembles the cold nature of ice, Such as the snowy mountains for example.

This is why when the armies start to fight no matter where you go your dragon will be at a dis-advantage to the dragons of that area.

Yours Sincerely
-x_o-Ezio-o_x-