You need to get a pet with the spritely/unicorn trait. It seems all the pets that came with the mega cards I've purchased will show the "amy cast spritely" trait as early as teen.
Your other option is to see if you can get someone with a pet with those traits to hatch with you and for you to train up your pet to see if they show it.
How do you get a pet that can heal your wizard in battle?
Ten percent luck, twenty percent skill
Fifteen percent concentrated power of will
Five percent mega-snack pleasure, fifty percent mini-game pain
And a hundred percent reason to remember........make sure you have a pet that can even learn a healing trait or hatch with someone that already has the trait.
That talent is called spritely. It makes your pet cast sprite when you get attacked. Not all pets have that. There is also Unicorn, which makes it cast unicorn.