betta water

Question
Ok so I have learned that betta aren't supposed to be kept in distilled water, which I had had
mine in; I learned that to switch types of water, you are supposed to do it gradually so as not to
shock the fish.  Instead of 100% distilled water, I switched to 50% distilled and 50% tap water
with drops in it....next week, i was going to make the switch to 100% tap water with drops in it,
or i was thinking about spring water; which is the best bet?  Also, today I noticed that there
were clusters of foamy white bubbles around the edges at the top of his bowl.  Is this normal?  
What does it mean?

Answer
Spring water is the worst.

Tap water is the best. Not sure why everybody gets caught up in all these water types. With saltwater it matters, with freshwater it really doesn't unless you have some really delicate fish. He would have been fine in distilled, but tap is good too.

Just make sure to use a tap water conditioner like Aquasafe or Seachem's Prime.

The foam is called a bubble nest. He made it because he wants to mate, he thinks some female is going to come along and lay eggs in his bubble nest. It just means he's happy.

-Nick