try using a grass type Pokemon like treecko evolutions or which ever you choose try having it around level 50 also
You have to make sure you don't step on the same spot twice or you'll fall down.
I reccommend having level 45-55 when fighting him, you can train by going back to fort tree and battleing the Pokemon there, and have some high lightning type, and you should rock that gym.
use lots of revives and hyper potions
it is a dragon type Pokemon gym
The third gym leader in Pokemon Sapphire is Wattson and he is located in Mauville City.
fire gym in lavaridge
the seventh gym in pokemon sapphire is in mossdeep city.
In sapphire, the 5th gym leader is your dad, in that city after Oakdale.
it is in petalburg near the Pokemon gym
In Pokemon Sapphire, Ruby and Emerald the 7th Gym that's located in Mossdeep City has Psychic type Pokemon.
In the gym.
You can with AR.
petalburg
In the lavaridge town gym.
the grass type gym