Last weekend I did a decor and plant overhaul on my big sorority tank, which included releasing the last of my new girls loose into it. All went fine, and all the fish were rewarded for their patience with a feed and a treat of freeze dried mysis from the "Dial a Treat" thingie. But the next day, Grif was at the top of the tank with SBD symptoms. I immediately caught her in a cup and moved her to a small QT tank.
She got over the tummy issue quickly, but on the second day when I came in to check her, she was huddled on the bottom leaning against the little clay pot hidey cave, and the poor girl was the very image of "depressed."
I put her back in the big tank the next day since the SBD symptoms were cleared up, and she instantly rejoined the group and was the very image of "Excited."
It's just suprising how much personality and emotion bettas can (or at least seem to) display!