I have lost nearly all my fish in a five day period. I have made x2 water changes. All my water parameters are good. I am using the aquarium coop dip sticks. This has never happened to me before. The only thing that is different in my tank is during the routine water change I removed a piece of driftwood. All was good for a bit then I began to loose fish. I lost 8 just this morning! My tank is heavily planted with many snails. Mystery, nitrite, and such. I have not lost any snails as of yet. My tank has cory’s, tetras, barbs, and a few danios. I would appreciate any advice.