bloated gold fish

Hi all ,

I have 29 gallon tank using mechanical top filter.
My pH is 6.5 to 7.0 and KH is 10 to 11 .
Ammonia is 5 mg/l

One of my goldfish is bloated . I have done 50% water changes and
added the Jungle Fish Intensise Medicine and some crsytal salt into the
tank.

However , the gold fish is still bloated and his body scales is
protruding.

Anybody have ideas and suggestions how to solve the problems.

Thanks.