Hi everyone 👋 what is Paras best nature please?

I've started a new run and picked Bulbasaur as my starter, I'm going to use it's type as my theme as I progress through the run, so grass and poison types will be my team theme. I've got Beedrill and Nidoran F currently, but want to add Paras, should I go for adamant or bulk up it's defense with impish? Leaning towards adamant for the extra attack, what would suit it best having 4x weakness to fire and flying and dreadful speed stats?