This is pretty much the place. There are some good betta folk who tour through from time to time and one of them will be able to help.
They'll want to know how long you've had the fish, what the fish is in (small tank, bowl, little container -- include the size, even if its a guess). How often do you change the water and how much do you change? How do you treat the water before each change (dechlorinator, anything else)? How much do you feed and how often? Just the basics about the enviroment.
Just some quick basics to start:
Bettas can do room temp, but actually like a little warmer -- keep them out of drafts and somewhere a little warm is better.
The vases are no good. If its in a vase get a bowl. Some people use mason jars. Not sure of the minimum size, but you want at least a quart or two -- the little containers are really a little too small. I'd get at least a one gallon fishbowl.
The fish gives off ammonia as a waste product, and eventually will poison itself. (This is why a little more room is better: doesn't happen as fast). The water needs to be changed on a regular basis. I'd say once a week, but its really as often as necessary. You should probably get an ammonia test kit so you can check.
The tapwater has chlorine or chloramines in it. These are bad for the fish. You need a dechlorinator for the new water at each change. I use Amquel, which will take care of either.
They don't need a whole lot of food: don't overfeed! (Again with the ammonia: more food=more waste).
A little gravel or sand on the bottom and a little silk plant can go a long way towards making it feel safe. Even if you're doing everything else right, it might just be stressed out.
Good luck and welcome
