Yogurt is very good for thrush. You can also buy probiotics in the capsule form. It will put good bacteria back into your mouth even after you already have it.

I also got thrush from antibiotics and I never took anything for it I just ate yogurt and took probiotics.
References :

Really? I knew a guy that got one from going down on a chick that had one but never heard you could get it from antibiotics.
References :

What is good/bad to eat when you have thrush (oral yeast infection)?
I came down with one after being on antibiotics, since those can mess up the balance of organisms in your body. I’ve already gone to the doctor and have a prescription to treat it, but they said it’ll be a week probably before it really starts working. In the mean time, what is good or bad to eat? Like I know yogurt helps prevent such infections, but I didn’t know if it was also good once you already have one.
Yes, you can.
"Medications that upset the balance of microorganisms in the mouth and may cause thrush include corticosteroids, antibiotics, and birth control pills." -WebMD