sick puffer

Question
I have a brackish-water puffer that is about 2 inches big.  It has been stressing out pretty bad off and on lately for about 2 weeks.  Right now he is not really eating, he's turning very dark colors, is swimming upside down towards the bottom or else just "lays" on the bottom of the tank not swimming at all and is breathing funny.  I have done several water changes,and added plenty of aquarium salt, and every time I add the salt, he will swim to the salt and swim in it.  I was wondering if he was getting too big and needed to be switched completely to salt water or if there is another problem here.  Please give me your best advice.  Thank you.

Answer
Brandon,                                                     Your puff is an adult now and needs to be truly brackish. This is 1/3 cup of sea salt to 1 gallon of water. Make him up a new tank. Sea salt and aquarium salt are two different things.Make it all natural colors gravel and plants. Add a nice scat and maybe a mono sabae... a couple of bumble bee gobys. Brackish tanks are as easy to keep as fresh. All the same rules about cleaning. The only thing is mix your salt with water separately and add with your fresh water..... try to dissolve as thoroughly as possible. I never used a specific gravity meter with mine. I just estimated the amount of gallons I took out during a water change and added salt to the new water accordingly.Go to your petshop and get some instant ocean quick or you are going to lose him.Try to keep your ph about 7.8....you can do this with baking soda. It is sodium bicarbonate ph up. Good Luck,Tina