okay guys, i really need help! i got a new baby flowerhorn, and put it in my 10 gallon tank, i changed new water and added stress coat and appropriate amount of salt, when i read the PH of the water right after this, it is green reading 7.0 but then a few hours later i notice my FH is stressed, and i read the PH again, but it turn yellow! (6.0)!! i have done 50% water changes, but still the same, then i was like fck it 100% water change but still the same! i've cleaned everything over and over again i dont feed him but the water still goes to acidic levels! how do i stop this?! my fish is starting to get very stressed out and i'm just stumped on what to do!