I have had my betta for 6 months. He hasn't ate in atleast 12 days. Very skinny and his spine looks curved. Took him to where i bought him and they gave me drops to make the water safe when i change it and betta fix. Other then being skinny and curved spine his fins and scales look healthy. i've tried 3 different foods. He acts interested but has only nibbled once. since I started to treat the water theres been this film on the top of the water I keep removing. I don't want him to suffer any longer. I need to help the poor guy. They tested the water when I took him in and everything was fine. He is in a half gallon bowel no filter. Normally change after the water once a week and clean the entire tank once a month but only change half the water. Please help.