I use Indian Almond leaves (IAL). They have anti-bacterial proprieties, and stain the water a nice tea colour, which, in my opinion, looks natural.
I use them all the time for my Bettas, it's wonderful stuff.. works miracles. For bettas, also entices them to spawn, and makes their nests "sticker", so they stay together better.
IAL are great for fungus, I put my axolotl in a tub with IAL in it when he had fungus - it was soon gone, no salt baths (although if it's really aggressive, I would still do salt baths).
I get mine from
HERE I highly recommend this couple, they are so helpful and kind. One time there was a mishap getting them into Australia from QT (QT's mistake), and they went above and beyond to get the leaves to us. There is lots of info on their site.
As for tea-bags, you can, but make sure it is de-caffeinated, you don't want to poison your axies with caffeine!
There is also another good link to a previous topic, here,
http://www.caudata.org/forum/f46-be...ters-substrate/79062-tea-tank.html#post304614
