i have a veil tail betta in a 5 gal aquarium. i went on vacation for a few days (left in a dissolving betta feeder) and when i returned my betta was hardly moving he either sits at the bottom or floats at the top and moves his gills but nothing else. i fed him a little and he ate some. i did a water change and it did not help so i changed even a little bit more because it did seem a little dirty. anything else i could do? i am worried he won't make it. no other bad symptoms.