can any1 help me diagnose my fishy's problem.

its a small comit gold fish living alone in its tank. lately i noticed he wasn't eating very well (fussy about eating fish flakes).
i had noticed some constipation.
i change the water regulary.
he had a white spot on his tail, which i have been treating.
NOW TODAY HIS FINNS ARE CLAMPED AND HE IS JUST FLOATING NEAR THE BOTTOM.

COULD THIS BE THE END OF A HAPPY STORY, OR IS THERE STILL CHANCE FOR MY LITTLE FISHY.

Hi there fatso -could you answer the questions as best you can from the red box
so you can get the right help. The water parems are very important in determining the problem your fish is having.