I hope someone can help. I have a 65 gallon African cichlid tank that is established. My fish are dying and I cannot figure out why. At this point I considered an autopsy and there is nowhere to have that done. all of my numbers are fine. I strip tested my water, I liquid tested my water and I have taken it to two other places as well and they all say the water is fine. The fish are whole with no signs of anything different. I have done three water changes. The fish appeared fine on Sunday morning and Sunday afternoon when I got home there were tow dead in the tank and it has not stopped yet for a total loss of eight and one on the way out now. I change my water and clean my tank faithfully every Thursday. The fish seem to isolate at the top, stop eating and then die this happens within days. Please help.