When you do the water change, don't remove all the water or 'swish' the rocks. What you're going to want to do is leave the fish in the tank and do about a 50% water change, with a gravel siphon, simultaneously cleaning the gravel while pulling the water out. Changing all the water and moving the fish is very stressful. When you add water after removing it, use a tap water conditioner, such as Prime by Seachem.
Did you use a conditioner when you changed the water? Is there a heater/filter in the tank?
I'm thinking your tank has not yet cycled (Read more here http://www.tropicalfishkeeping.com/f...m-cycle-38617/
) and that your fish is suffering from ammonia poisoning, which I'm not seeing a result for. Sounds like you're using test strips. You may want to look into purchasing API Liquid Master test. Your Nitrates are also quite high, this is a contributing factor.
The only way I can see atm to help him is to do daily water changes in the manner described above until your tank has cycled (Ammonia 0, Nitrite 0, Nitrate <10)