Why is my New Betta Fish not doing anything?

when we had a beta fish, we put him by a mirror, but i dont think that really had any effect on him.. males dont really like other fish and they'll blow and puff up if they see one. he probably just needs time to adjust to his new home. and putting him in a little bit- little bit- of sunlight will probably help lighten his mood. what kind of water did you use? i know its not safe to use reg tap water, but use like purified water, you know, from the bottles or jugs. Good luck!