Puzzles and Survival, Campaign Chapter III Level 11-7 (Very Hard If Pick Wrong Heroes)

I've been hundred of times trying this Level but failed. All heroes will be died when got poison attack just in 2 rounds.
I just realised lately that I need to counter the poison attack from the monster. So I think this is the best combo heroes to pick for this Level.
The heroes I picked:
- Fox because it can remove poison
- Mantis can remove potion too while doing damage
- Chia-hao: The most important hero because it can make immune to all poison damage.