Yes I have used tea tree oil on my fungus and it did work, but it took about 5 months before the fungus wasn't showing anymore. I finally switiched over to a product that had tea tree oilin it but with some other ingredients too. It was called "Futspa" (Search for it on Google). I liked the idea of mixed and it was gone in 3 weeks. although of course I had been working on it for so long.
But if I had to do it again, I would start with a mixed product.
Thanks and good luck
gerry