So I have a betta fish that I've been keeping in a 2.5 gal tank for about 5-6 months now. I've been a little worried because as of late he's acting a bit sick yet when I examine him there's nothing wrong with him. If I come by his tank he will still swim over to greet me but other than that he just lays in his leaf and if not there the very bottom. Lately when I try to feed him he attempts to eat the pellets to no avail. He snaps 3-4 times at it before just giving up. He's always gotten it down on the first try.
I've tried a 50% water change and it hasn't helped anything but I might try a 100% change very soon. I know he was constipated a few days ago but he passed a very large stool & he isn't looking swollen anymore. Currently I have him in a small round vase just so that he doesn't have to exert himself to get to the surface for air but I'm not sure where to go with this. Any advice?