I had 2 bass, some sunfish, etc. I just did a water change about 4hr ago, and One bass is dead and the other is barely alive and breathing hard. I used declore, some ph up, and some flourish excel. the flourish excel and ph increase I used at half dose. the water was changed about 30%. They were thriving yesterday. I need help soon so my other bass doesn't die. all of my other fish are ok.