its been almost 2 months

[chardonnay]

since my fish has been sick. Ive had her for almost a year now and she has always had the same tank it is half gallon. but the last two months she has eaten little no nothing swimming with almost a arched back lies on the bottom of the tank on her side then swims really fast to the top for air. she was white now her scales look dirty like back underneath most. her fins look torn and she seems like she has no energy. her tank is constantly at 75 degrees which always seemed good for her. i don't know what to do. I though she had swim bladder but when i treated her for it she didn't get better??? any ideas what might be wrong?

[sunkissedinCA]

how often do you do water changes?

[chardonnay]

i used to change it once a week, but now everyday.